Mike Romain

The TJ has an upper and lower arm so the axle does indeed drop almost
straight down. The gent's photos show an upper control arm.

I know the spring still sits flat at full droop because I have helped
replace them.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Peter Pontbriand wrote:
>
> But, when the axle droops it doesn't drop straight down, it moves though an
> arc. The length of the control arms is fixed, so the whole axle assembly
> essentially pivots around the frame control arm mounts. Given that, if the
> transfer case output is lower than this pivot point, the driveshaft is going
> to compress.
>
> /Peter
>
> "twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy.c om...
> > No. Your pumpkin end is lower than your xfer case end. If you droop the
> > axle, it moves further away from the xfer case output shaft and becomes
> > longer.
> >
> > Peter Pontbriand wrote:
> >
> > > Full droop would shorten the drive shaft on a suspension like that,
> wouldn't
> > > it? I think the t-case output is lower than the frame-end control arm
> > > mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
> a
> > > lift as compared to when it's sitting on it's wheels, even with the
> raised
> > > t-case skid.
> > >
> > > /Peter
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:4187946D.85A9BF4B@sympatico.ca...
> > >
> > >>The oil spray is common for rust protection.
> > >>
> > >>Your rear pinion angle looks almost right from the angle the photo
> > >>shows. It is supposed to be pointing square at the driveshaft.
> > >>
> > >>If you jack up the rear of the Jeep and let the axle hang in space, it
> > >>can give you an idea if the axle is long enough. There is a spline slip
> > >>joint in the axle. If it is only say 1/4 the way out at full droop,
> > >>then likely you have tons of room to raise that plate back up where it
> > >>should be.
> > >>
> > >>While it's drooped you could at least unbolt the t-case end and just
> > >>hand place it up higher to see if it extends enough.
> > >>
> > >>Mike
> > >>
> > >>JimG wrote:
> > >>
> > >>>No adjustable control arms:
> > >>>
> > >>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> > >>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> > >>>
> > >>>Hey Mike... notice the oil sprayed under there? This Jeep was from
> > >>>Buffalo... the guy told me that was common practice in the north for
> > >
> > > rust
> > >
> > >>>prevention. Do they do that in Canada?
> > >>>
> > >>>JimG
> > >>>
> > >>>"twaldron" wrote in message ...
> > >>>
> > >>>>Here is my theory FWIW:
> > >>>>
> > >>>>The orig owner may have first passed on installing adj. control arms
> > >
> > > and
> > >
> > >>>>used the drop kit instead, thinking he was saving money. After
> > >>>>experiencing some driveline vibes even with the drop kit, he installed
> > >>>>the CV driveshaft. JimG might have to buy some adj. control arms to
> > >>>>complete the job. Of course, I'm going on one photo that does not show
> > >>>>everything (including a drop kit) and a vivid imagination.
> > >>>>
> > >>>>So what of it, JimG...do you have any adj. upper control arms?
> > >>>>
> > >
> > >
> > >
> >
> > --
> > __________________________________________________ _________
> > tw
> >
> > 71 Bill Stroppe Baja Bronco
> > 03 TJ Rubicon - Rubicon Express 4.5"
> > 01 XJ Sport
> >
> > There is a very fine line between "hobby" and "mental illness."
> > -- Dave Barry
> >
> > Pronunciation: 'jEp
> > Function: noun
> > Date: 1940
> >
> > Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> > A small general-purpose motor vehicle with 80-inch wheelbase,
> > 1/4-ton capacity, and four-wheel drive used by the U.S. army in
> > World War II.
> >
> > (Please remove the OBVIOUS to reply by email)
> > __________________________________________________ _________

Mike Romain

The TJ has an upper and lower arm so the axle does indeed drop almost
straight down. The gent's photos show an upper control arm.

I know the spring still sits flat at full droop because I have helped
replace them.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Peter Pontbriand wrote:
>
> But, when the axle droops it doesn't drop straight down, it moves though an
> arc. The length of the control arms is fixed, so the whole axle assembly
> essentially pivots around the frame control arm mounts. Given that, if the
> transfer case output is lower than this pivot point, the driveshaft is going
> to compress.
>
> /Peter
>
> "twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy.c om...
> > No. Your pumpkin end is lower than your xfer case end. If you droop the
> > axle, it moves further away from the xfer case output shaft and becomes
> > longer.
> >
> > Peter Pontbriand wrote:
> >
> > > Full droop would shorten the drive shaft on a suspension like that,
> wouldn't
> > > it? I think the t-case output is lower than the frame-end control arm
> > > mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
> a
> > > lift as compared to when it's sitting on it's wheels, even with the
> raised
> > > t-case skid.
> > >
> > > /Peter
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:4187946D.85A9BF4B@sympatico.ca...
> > >
> > >>The oil spray is common for rust protection.
> > >>
> > >>Your rear pinion angle looks almost right from the angle the photo
> > >>shows. It is supposed to be pointing square at the driveshaft.
> > >>
> > >>If you jack up the rear of the Jeep and let the axle hang in space, it
> > >>can give you an idea if the axle is long enough. There is a spline slip
> > >>joint in the axle. If it is only say 1/4 the way out at full droop,
> > >>then likely you have tons of room to raise that plate back up where it
> > >>should be.
> > >>
> > >>While it's drooped you could at least unbolt the t-case end and just
> > >>hand place it up higher to see if it extends enough.
> > >>
> > >>Mike
> > >>
> > >>JimG wrote:
> > >>
> > >>>No adjustable control arms:
> > >>>
> > >>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> > >>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> > >>>
> > >>>Hey Mike... notice the oil sprayed under there? This Jeep was from
> > >>>Buffalo... the guy told me that was common practice in the north for
> > >
> > > rust
> > >
> > >>>prevention. Do they do that in Canada?
> > >>>
> > >>>JimG
> > >>>
> > >>>"twaldron" wrote in message ...
> > >>>
> > >>>>Here is my theory FWIW:
> > >>>>
> > >>>>The orig owner may have first passed on installing adj. control arms
> > >
> > > and
> > >
> > >>>>used the drop kit instead, thinking he was saving money. After
> > >>>>experiencing some driveline vibes even with the drop kit, he installed
> > >>>>the CV driveshaft. JimG might have to buy some adj. control arms to
> > >>>>complete the job. Of course, I'm going on one photo that does not show
> > >>>>everything (including a drop kit) and a vivid imagination.
> > >>>>
> > >>>>So what of it, JimG...do you have any adj. upper control arms?
> > >>>>
> > >
> > >
> > >
> >
> > --
> > __________________________________________________ _________
> > tw
> >
> > 71 Bill Stroppe Baja Bronco
> > 03 TJ Rubicon - Rubicon Express 4.5"
> > 01 XJ Sport
> >
> > There is a very fine line between "hobby" and "mental illness."
> > -- Dave Barry
> >
> > Pronunciation: 'jEp
> > Function: noun
> > Date: 1940
> >
> > Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> > A small general-purpose motor vehicle with 80-inch wheelbase,
> > 1/4-ton capacity, and four-wheel drive used by the U.S. army in
> > World War II.
> >
> > (Please remove the OBVIOUS to reply by email)
> > __________________________________________________ _________

Steve

Hi Mike,

Peter's right on that one. The TJ lower control arms are fixed to the
frame between the t-case and axle. In other words, the radius of the
control arm arc is shorter than the radius of the drive shaft arc. When
the axle drops on the control arm arc, it gets closer to the t-case and
compresses the drive shaft.

By the way Peter, a lowered t-case will exaggerate the drive shaft
compression but the shaft will compress even with the t-case cross
member in the stock position.

The upper arms pull the pinion angle down as the axle drops, so distance
from pinion to t-case is increased a tiny bit, but this is relatively
insignificant compared to the amount the distance is shortened as the
axle drops on the lower control arm arc.

My front shaft definitely compresses when the axle is hanging fully down.

Steve
http://xjeep.dyndns.org


Mike Romain wrote:
> The TJ has an upper and lower arm so the axle does indeed drop almost
> straight down. The gent's photos show an upper control arm.
>
> I know the spring still sits flat at full droop because I have helped
> replace them.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Peter Pontbriand wrote:
>
>>But, when the axle droops it doesn't drop straight down, it moves though an
>>arc. The length of the control arms is fixed, so the whole axle assembly
>>essentially pivots around the frame control arm mounts. Given that, if the
>>transfer case output is lower than this pivot point, the driveshaft is going
>>to compress.
>>
>>/Peter
>>
>>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
>>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
>>
>>>No. Your pumpkin end is lower than your xfer case end. If you droop the
>>>axle, it moves further away from the xfer case output shaft and becomes
>>>longer.
>>>
>>>Peter Pontbriand wrote:
>>>
>>>
>>>>Full droop would shorten the drive shaft on a suspension like that,
>>
>>wouldn't
>>
>>>>it? I think the t-case output is lower than the frame-end control arm
>>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
>>
>>a
>>
>>>>lift as compared to when it's sitting on it's wheels, even with the
>>
>>raised
>>
>>>>t-case skid.
>>>>
>>>>/Peter
>>>>
>>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
>>>>news:4187946D.85A9BF4B@sympatico.ca...
>>>>
>>>>
>>>>>The oil spray is common for rust protection.
>>>>>
>>>>>Your rear pinion angle looks almost right from the angle the photo
>>>>>shows. It is supposed to be pointing square at the driveshaft.
>>>>>
>>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
>>>>>can give you an idea if the axle is long enough. There is a spline slip
>>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
>>>>>then likely you have tons of room to raise that plate back up where it
>>>>>should be.
>>>>>
>>>>>While it's drooped you could at least unbolt the t-case end and just
>>>>>hand place it up higher to see if it extends enough.
>>>>>
>>>>>Mike
>>>>>
>>>>>JimG wrote:
>>>>>
>>>>>
>>>>>>No adjustable control arms:
>>>>>>
>>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
>>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
>>>>>>
>>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
>>>>>>Buffalo... the guy told me that was common practice in the north for
>>>>
>>>>rust
>>>>
>>>>
>>>>>>prevention. Do they do that in Canada?
>>>>>>
>>>>>>JimG
>>>>>>
>>>>>>"twaldron" wrote in message ...
>>>>>>
>>>>>>
>>>>>>>Here is my theory FWIW:
>>>>>>>
>>>>>>>The orig owner may have first passed on installing adj. control arms
>>>>
>>>>and
>>>>
>>>>
>>>>>>>used the drop kit instead, thinking he was saving money. After
>>>>>>>experiencing some driveline vibes even with the drop kit, he installed
>>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
>>>>>>>complete the job. Of course, I'm going on one photo that does not show
>>>>>>>everything (including a drop kit) and a vivid imagination.
>>>>>>>
>>>>>>>So what of it, JimG...do you have any adj. upper control arms?
>>>>>>>
>>>>
>>>>
>>>>
>>>--
>>>_______________________________________________ ____________
>>>tw
>>>
>>>71 Bill Stroppe Baja Bronco
>>>03 TJ Rubicon - Rubicon Express 4.5"
>>>01 XJ Sport
>>>
>>>There is a very fine line between "hobby" and "mental illness."
>>>-- Dave Barry
>>>
>>>Pronunciation: 'jEp
>>>Function: noun
>>>Date: 1940
>>>
>>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
>>>A small general-purpose motor vehicle with 80-inch wheelbase,
>>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
>>>World War II.
>>>
>>>(Please remove the OBVIOUS to reply by email)
>>>_______________________________________________ ____________

Steve

Hi Mike,

Peter's right on that one. The TJ lower control arms are fixed to the
frame between the t-case and axle. In other words, the radius of the
control arm arc is shorter than the radius of the drive shaft arc. When
the axle drops on the control arm arc, it gets closer to the t-case and
compresses the drive shaft.

By the way Peter, a lowered t-case will exaggerate the drive shaft
compression but the shaft will compress even with the t-case cross
member in the stock position.

The upper arms pull the pinion angle down as the axle drops, so distance
from pinion to t-case is increased a tiny bit, but this is relatively
insignificant compared to the amount the distance is shortened as the
axle drops on the lower control arm arc.

My front shaft definitely compresses when the axle is hanging fully down.

Steve
http://xjeep.dyndns.org


Mike Romain wrote:
> The TJ has an upper and lower arm so the axle does indeed drop almost
> straight down. The gent's photos show an upper control arm.
>
> I know the spring still sits flat at full droop because I have helped
> replace them.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Peter Pontbriand wrote:
>
>>But, when the axle droops it doesn't drop straight down, it moves though an
>>arc. The length of the control arms is fixed, so the whole axle assembly
>>essentially pivots around the frame control arm mounts. Given that, if the
>>transfer case output is lower than this pivot point, the driveshaft is going
>>to compress.
>>
>>/Peter
>>
>>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
>>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
>>
>>>No. Your pumpkin end is lower than your xfer case end. If you droop the
>>>axle, it moves further away from the xfer case output shaft and becomes
>>>longer.
>>>
>>>Peter Pontbriand wrote:
>>>
>>>
>>>>Full droop would shorten the drive shaft on a suspension like that,
>>
>>wouldn't
>>
>>>>it? I think the t-case output is lower than the frame-end control arm
>>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
>>
>>a
>>
>>>>lift as compared to when it's sitting on it's wheels, even with the
>>
>>raised
>>
>>>>t-case skid.
>>>>
>>>>/Peter
>>>>
>>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
>>>>news:4187946D.85A9BF4B@sympatico.ca...
>>>>
>>>>
>>>>>The oil spray is common for rust protection.
>>>>>
>>>>>Your rear pinion angle looks almost right from the angle the photo
>>>>>shows. It is supposed to be pointing square at the driveshaft.
>>>>>
>>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
>>>>>can give you an idea if the axle is long enough. There is a spline slip
>>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
>>>>>then likely you have tons of room to raise that plate back up where it
>>>>>should be.
>>>>>
>>>>>While it's drooped you could at least unbolt the t-case end and just
>>>>>hand place it up higher to see if it extends enough.
>>>>>
>>>>>Mike
>>>>>
>>>>>JimG wrote:
>>>>>
>>>>>
>>>>>>No adjustable control arms:
>>>>>>
>>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
>>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
>>>>>>
>>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
>>>>>>Buffalo... the guy told me that was common practice in the north for
>>>>
>>>>rust
>>>>
>>>>
>>>>>>prevention. Do they do that in Canada?
>>>>>>
>>>>>>JimG
>>>>>>
>>>>>>"twaldron" wrote in message ...
>>>>>>
>>>>>>
>>>>>>>Here is my theory FWIW:
>>>>>>>
>>>>>>>The orig owner may have first passed on installing adj. control arms
>>>>
>>>>and
>>>>
>>>>
>>>>>>>used the drop kit instead, thinking he was saving money. After
>>>>>>>experiencing some driveline vibes even with the drop kit, he installed
>>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
>>>>>>>complete the job. Of course, I'm going on one photo that does not show
>>>>>>>everything (including a drop kit) and a vivid imagination.
>>>>>>>
>>>>>>>So what of it, JimG...do you have any adj. upper control arms?
>>>>>>>
>>>>
>>>>
>>>>
>>>--
>>>_______________________________________________ ____________
>>>tw
>>>
>>>71 Bill Stroppe Baja Bronco
>>>03 TJ Rubicon - Rubicon Express 4.5"
>>>01 XJ Sport
>>>
>>>There is a very fine line between "hobby" and "mental illness."
>>>-- Dave Barry
>>>
>>>Pronunciation: 'jEp
>>>Function: noun
>>>Date: 1940
>>>
>>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
>>>A small general-purpose motor vehicle with 80-inch wheelbase,
>>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
>>>World War II.
>>>
>>>(Please remove the OBVIOUS to reply by email)
>>>_______________________________________________ ____________

Steve

Hi Mike,

Peter's right on that one. The TJ lower control arms are fixed to the
frame between the t-case and axle. In other words, the radius of the
control arm arc is shorter than the radius of the drive shaft arc. When
the axle drops on the control arm arc, it gets closer to the t-case and
compresses the drive shaft.

By the way Peter, a lowered t-case will exaggerate the drive shaft
compression but the shaft will compress even with the t-case cross
member in the stock position.

The upper arms pull the pinion angle down as the axle drops, so distance
from pinion to t-case is increased a tiny bit, but this is relatively
insignificant compared to the amount the distance is shortened as the
axle drops on the lower control arm arc.

My front shaft definitely compresses when the axle is hanging fully down.

Steve
http://xjeep.dyndns.org


Mike Romain wrote:
> The TJ has an upper and lower arm so the axle does indeed drop almost
> straight down. The gent's photos show an upper control arm.
>
> I know the spring still sits flat at full droop because I have helped
> replace them.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Peter Pontbriand wrote:
>
>>But, when the axle droops it doesn't drop straight down, it moves though an
>>arc. The length of the control arms is fixed, so the whole axle assembly
>>essentially pivots around the frame control arm mounts. Given that, if the
>>transfer case output is lower than this pivot point, the driveshaft is going
>>to compress.
>>
>>/Peter
>>
>>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
>>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
>>
>>>No. Your pumpkin end is lower than your xfer case end. If you droop the
>>>axle, it moves further away from the xfer case output shaft and becomes
>>>longer.
>>>
>>>Peter Pontbriand wrote:
>>>
>>>
>>>>Full droop would shorten the drive shaft on a suspension like that,
>>
>>wouldn't
>>
>>>>it? I think the t-case output is lower than the frame-end control arm
>>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
>>
>>a
>>
>>>>lift as compared to when it's sitting on it's wheels, even with the
>>
>>raised
>>
>>>>t-case skid.
>>>>
>>>>/Peter
>>>>
>>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
>>>>news:4187946D.85A9BF4B@sympatico.ca...
>>>>
>>>>
>>>>>The oil spray is common for rust protection.
>>>>>
>>>>>Your rear pinion angle looks almost right from the angle the photo
>>>>>shows. It is supposed to be pointing square at the driveshaft.
>>>>>
>>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
>>>>>can give you an idea if the axle is long enough. There is a spline slip
>>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
>>>>>then likely you have tons of room to raise that plate back up where it
>>>>>should be.
>>>>>
>>>>>While it's drooped you could at least unbolt the t-case end and just
>>>>>hand place it up higher to see if it extends enough.
>>>>>
>>>>>Mike
>>>>>
>>>>>JimG wrote:
>>>>>
>>>>>
>>>>>>No adjustable control arms:
>>>>>>
>>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
>>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
>>>>>>
>>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
>>>>>>Buffalo... the guy told me that was common practice in the north for
>>>>
>>>>rust
>>>>
>>>>
>>>>>>prevention. Do they do that in Canada?
>>>>>>
>>>>>>JimG
>>>>>>
>>>>>>"twaldron" wrote in message ...
>>>>>>
>>>>>>
>>>>>>>Here is my theory FWIW:
>>>>>>>
>>>>>>>The orig owner may have first passed on installing adj. control arms
>>>>
>>>>and
>>>>
>>>>
>>>>>>>used the drop kit instead, thinking he was saving money. After
>>>>>>>experiencing some driveline vibes even with the drop kit, he installed
>>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
>>>>>>>complete the job. Of course, I'm going on one photo that does not show
>>>>>>>everything (including a drop kit) and a vivid imagination.
>>>>>>>
>>>>>>>So what of it, JimG...do you have any adj. upper control arms?
>>>>>>>
>>>>
>>>>
>>>>
>>>--
>>>_______________________________________________ ____________
>>>tw
>>>
>>>71 Bill Stroppe Baja Bronco
>>>03 TJ Rubicon - Rubicon Express 4.5"
>>>01 XJ Sport
>>>
>>>There is a very fine line between "hobby" and "mental illness."
>>>-- Dave Barry
>>>
>>>Pronunciation: 'jEp
>>>Function: noun
>>>Date: 1940
>>>
>>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
>>>A small general-purpose motor vehicle with 80-inch wheelbase,
>>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
>>>World War II.
>>>
>>>(Please remove the OBVIOUS to reply by email)
>>>_______________________________________________ ____________

Mike Romain

I could be mistaken, but I don't buy your explanation at all.

The driveshaft pivot is up high on the t-case. The control arm front
pivot is low below the frame. The arc the lower arm describes will make
the driveshaft extend as it goes down.

It is the lower arc's lower center that will draw the driveshaft out.

I will look real close next time I see a TJ hoisted, that's for sure.
My curiosity is up.

Mike

Steve wrote:
>
> Hi Mike,
>
> Peter's right on that one. The TJ lower control arms are fixed to the
> frame between the t-case and axle. In other words, the radius of the
> control arm arc is shorter than the radius of the drive shaft arc. When
> the axle drops on the control arm arc, it gets closer to the t-case and
> compresses the drive shaft.
>
> By the way Peter, a lowered t-case will exaggerate the drive shaft
> compression but the shaft will compress even with the t-case cross
> member in the stock position.
>
> The upper arms pull the pinion angle down as the axle drops, so distance
> from pinion to t-case is increased a tiny bit, but this is relatively
> insignificant compared to the amount the distance is shortened as the
> axle drops on the lower control arm arc.
>
> My front shaft definitely compresses when the axle is hanging fully down.
>
> Steve
> http://xjeep.dyndns.org
>
> Mike Romain wrote:
> > The TJ has an upper and lower arm so the axle does indeed drop almost
> > straight down. The gent's photos show an upper control arm.
> >
> > I know the spring still sits flat at full droop because I have helped
> > replace them.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Peter Pontbriand wrote:
> >
> >>But, when the axle droops it doesn't drop straight down, it moves though an
> >>arc. The length of the control arms is fixed, so the whole axle assembly
> >>essentially pivots around the frame control arm mounts. Given that, if the
> >>transfer case output is lower than this pivot point, the driveshaft is going
> >>to compress.
> >>
> >>/Peter
> >>
> >>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> >>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
> >>
> >>>No. Your pumpkin end is lower than your xfer case end. If you droop the
> >>>axle, it moves further away from the xfer case output shaft and becomes
> >>>longer.
> >>>
> >>>Peter Pontbriand wrote:
> >>>
> >>>
> >>>>Full droop would shorten the drive shaft on a suspension like that,
> >>
> >>wouldn't
> >>
> >>>>it? I think the t-case output is lower than the frame-end control arm
> >>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
> >>
> >>a
> >>
> >>>>lift as compared to when it's sitting on it's wheels, even with the
> >>
> >>raised
> >>
> >>>>t-case skid.
> >>>>
> >>>>/Peter
> >>>>
> >>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
> >>>>news:4187946D.85A9BF4B@sympatico.ca...
> >>>>
> >>>>
> >>>>>The oil spray is common for rust protection.
> >>>>>
> >>>>>Your rear pinion angle looks almost right from the angle the photo
> >>>>>shows. It is supposed to be pointing square at the driveshaft.
> >>>>>
> >>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
> >>>>>can give you an idea if the axle is long enough. There is a spline slip
> >>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
> >>>>>then likely you have tons of room to raise that plate back up where it
> >>>>>should be.
> >>>>>
> >>>>>While it's drooped you could at least unbolt the t-case end and just
> >>>>>hand place it up higher to see if it extends enough.
> >>>>>
> >>>>>Mike
> >>>>>
> >>>>>JimG wrote:
> >>>>>
> >>>>>
> >>>>>>No adjustable control arms:
> >>>>>>
> >>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> >>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> >>>>>>
> >>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
> >>>>>>Buffalo... the guy told me that was common practice in the north for
> >>>>
> >>>>rust
> >>>>
> >>>>
> >>>>>>prevention. Do they do that in Canada?
> >>>>>>
> >>>>>>JimG
> >>>>>>
> >>>>>>"twaldron" wrote in message ...
> >>>>>>
> >>>>>>
> >>>>>>>Here is my theory FWIW:
> >>>>>>>
> >>>>>>>The orig owner may have first passed on installing adj. control arms
> >>>>
> >>>>and
> >>>>
> >>>>
> >>>>>>>used the drop kit instead, thinking he was saving money. After
> >>>>>>>experiencing some driveline vibes even with the drop kit, he installed
> >>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
> >>>>>>>complete the job. Of course, I'm going on one photo that does not show
> >>>>>>>everything (including a drop kit) and a vivid imagination.
> >>>>>>>
> >>>>>>>So what of it, JimG...do you have any adj. upper control arms?
> >>>>>>>
> >>>>
> >>>>
> >>>>
> >>>--
> >>>_______________________________________________ ____________
> >>>tw
> >>>
> >>>71 Bill Stroppe Baja Bronco
> >>>03 TJ Rubicon - Rubicon Express 4.5"
> >>>01 XJ Sport
> >>>
> >>>There is a very fine line between "hobby" and "mental illness."
> >>>-- Dave Barry
> >>>
> >>>Pronunciation: 'jEp
> >>>Function: noun
> >>>Date: 1940
> >>>
> >>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> >>>A small general-purpose motor vehicle with 80-inch wheelbase,
> >>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
> >>>World War II.
> >>>
> >>>(Please remove the OBVIOUS to reply by email)
> >>>_______________________________________________ ____________

Mike Romain

I could be mistaken, but I don't buy your explanation at all.

The driveshaft pivot is up high on the t-case. The control arm front
pivot is low below the frame. The arc the lower arm describes will make
the driveshaft extend as it goes down.

It is the lower arc's lower center that will draw the driveshaft out.

I will look real close next time I see a TJ hoisted, that's for sure.
My curiosity is up.

Mike

Steve wrote:
>
> Hi Mike,
>
> Peter's right on that one. The TJ lower control arms are fixed to the
> frame between the t-case and axle. In other words, the radius of the
> control arm arc is shorter than the radius of the drive shaft arc. When
> the axle drops on the control arm arc, it gets closer to the t-case and
> compresses the drive shaft.
>
> By the way Peter, a lowered t-case will exaggerate the drive shaft
> compression but the shaft will compress even with the t-case cross
> member in the stock position.
>
> The upper arms pull the pinion angle down as the axle drops, so distance
> from pinion to t-case is increased a tiny bit, but this is relatively
> insignificant compared to the amount the distance is shortened as the
> axle drops on the lower control arm arc.
>
> My front shaft definitely compresses when the axle is hanging fully down.
>
> Steve
> http://xjeep.dyndns.org
>
> Mike Romain wrote:
> > The TJ has an upper and lower arm so the axle does indeed drop almost
> > straight down. The gent's photos show an upper control arm.
> >
> > I know the spring still sits flat at full droop because I have helped
> > replace them.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Peter Pontbriand wrote:
> >
> >>But, when the axle droops it doesn't drop straight down, it moves though an
> >>arc. The length of the control arms is fixed, so the whole axle assembly
> >>essentially pivots around the frame control arm mounts. Given that, if the
> >>transfer case output is lower than this pivot point, the driveshaft is going
> >>to compress.
> >>
> >>/Peter
> >>
> >>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> >>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
> >>
> >>>No. Your pumpkin end is lower than your xfer case end. If you droop the
> >>>axle, it moves further away from the xfer case output shaft and becomes
> >>>longer.
> >>>
> >>>Peter Pontbriand wrote:
> >>>
> >>>
> >>>>Full droop would shorten the drive shaft on a suspension like that,
> >>
> >>wouldn't
> >>
> >>>>it? I think the t-case output is lower than the frame-end control arm
> >>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
> >>
> >>a
> >>
> >>>>lift as compared to when it's sitting on it's wheels, even with the
> >>
> >>raised
> >>
> >>>>t-case skid.
> >>>>
> >>>>/Peter
> >>>>
> >>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
> >>>>news:4187946D.85A9BF4B@sympatico.ca...
> >>>>
> >>>>
> >>>>>The oil spray is common for rust protection.
> >>>>>
> >>>>>Your rear pinion angle looks almost right from the angle the photo
> >>>>>shows. It is supposed to be pointing square at the driveshaft.
> >>>>>
> >>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
> >>>>>can give you an idea if the axle is long enough. There is a spline slip
> >>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
> >>>>>then likely you have tons of room to raise that plate back up where it
> >>>>>should be.
> >>>>>
> >>>>>While it's drooped you could at least unbolt the t-case end and just
> >>>>>hand place it up higher to see if it extends enough.
> >>>>>
> >>>>>Mike
> >>>>>
> >>>>>JimG wrote:
> >>>>>
> >>>>>
> >>>>>>No adjustable control arms:
> >>>>>>
> >>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> >>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> >>>>>>
> >>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
> >>>>>>Buffalo... the guy told me that was common practice in the north for
> >>>>
> >>>>rust
> >>>>
> >>>>
> >>>>>>prevention. Do they do that in Canada?
> >>>>>>
> >>>>>>JimG
> >>>>>>
> >>>>>>"twaldron" wrote in message ...
> >>>>>>
> >>>>>>
> >>>>>>>Here is my theory FWIW:
> >>>>>>>
> >>>>>>>The orig owner may have first passed on installing adj. control arms
> >>>>
> >>>>and
> >>>>
> >>>>
> >>>>>>>used the drop kit instead, thinking he was saving money. After
> >>>>>>>experiencing some driveline vibes even with the drop kit, he installed
> >>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
> >>>>>>>complete the job. Of course, I'm going on one photo that does not show
> >>>>>>>everything (including a drop kit) and a vivid imagination.
> >>>>>>>
> >>>>>>>So what of it, JimG...do you have any adj. upper control arms?
> >>>>>>>
> >>>>
> >>>>
> >>>>
> >>>--
> >>>_______________________________________________ ____________
> >>>tw
> >>>
> >>>71 Bill Stroppe Baja Bronco
> >>>03 TJ Rubicon - Rubicon Express 4.5"
> >>>01 XJ Sport
> >>>
> >>>There is a very fine line between "hobby" and "mental illness."
> >>>-- Dave Barry
> >>>
> >>>Pronunciation: 'jEp
> >>>Function: noun
> >>>Date: 1940
> >>>
> >>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> >>>A small general-purpose motor vehicle with 80-inch wheelbase,
> >>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
> >>>World War II.
> >>>
> >>>(Please remove the OBVIOUS to reply by email)
> >>>_______________________________________________ ____________

Mike Romain

I could be mistaken, but I don't buy your explanation at all.

The driveshaft pivot is up high on the t-case. The control arm front
pivot is low below the frame. The arc the lower arm describes will make
the driveshaft extend as it goes down.

It is the lower arc's lower center that will draw the driveshaft out.

I will look real close next time I see a TJ hoisted, that's for sure.
My curiosity is up.

Mike

Steve wrote:
>
> Hi Mike,
>
> Peter's right on that one. The TJ lower control arms are fixed to the
> frame between the t-case and axle. In other words, the radius of the
> control arm arc is shorter than the radius of the drive shaft arc. When
> the axle drops on the control arm arc, it gets closer to the t-case and
> compresses the drive shaft.
>
> By the way Peter, a lowered t-case will exaggerate the drive shaft
> compression but the shaft will compress even with the t-case cross
> member in the stock position.
>
> The upper arms pull the pinion angle down as the axle drops, so distance
> from pinion to t-case is increased a tiny bit, but this is relatively
> insignificant compared to the amount the distance is shortened as the
> axle drops on the lower control arm arc.
>
> My front shaft definitely compresses when the axle is hanging fully down.
>
> Steve
> http://xjeep.dyndns.org
>
> Mike Romain wrote:
> > The TJ has an upper and lower arm so the axle does indeed drop almost
> > straight down. The gent's photos show an upper control arm.
> >
> > I know the spring still sits flat at full droop because I have helped
> > replace them.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Peter Pontbriand wrote:
> >
> >>But, when the axle droops it doesn't drop straight down, it moves though an
> >>arc. The length of the control arms is fixed, so the whole axle assembly
> >>essentially pivots around the frame control arm mounts. Given that, if the
> >>transfer case output is lower than this pivot point, the driveshaft is going
> >>to compress.
> >>
> >>/Peter
> >>
> >>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> >>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
> >>
> >>>No. Your pumpkin end is lower than your xfer case end. If you droop the
> >>>axle, it moves further away from the xfer case output shaft and becomes
> >>>longer.
> >>>
> >>>Peter Pontbriand wrote:
> >>>
> >>>
> >>>>Full droop would shorten the drive shaft on a suspension like that,
> >>
> >>wouldn't
> >>
> >>>>it? I think the t-case output is lower than the frame-end control arm
> >>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ is on
> >>
> >>a
> >>
> >>>>lift as compared to when it's sitting on it's wheels, even with the
> >>
> >>raised
> >>
> >>>>t-case skid.
> >>>>
> >>>>/Peter
> >>>>
> >>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
> >>>>news:4187946D.85A9BF4B@sympatico.ca...
> >>>>
> >>>>
> >>>>>The oil spray is common for rust protection.
> >>>>>
> >>>>>Your rear pinion angle looks almost right from the angle the photo
> >>>>>shows. It is supposed to be pointing square at the driveshaft.
> >>>>>
> >>>>>If you jack up the rear of the Jeep and let the axle hang in space, it
> >>>>>can give you an idea if the axle is long enough. There is a spline slip
> >>>>>joint in the axle. If it is only say 1/4 the way out at full droop,
> >>>>>then likely you have tons of room to raise that plate back up where it
> >>>>>should be.
> >>>>>
> >>>>>While it's drooped you could at least unbolt the t-case end and just
> >>>>>hand place it up higher to see if it extends enough.
> >>>>>
> >>>>>Mike
> >>>>>
> >>>>>JimG wrote:
> >>>>>
> >>>>>
> >>>>>>No adjustable control arms:
> >>>>>>
> >>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> >>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> >>>>>>
> >>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was from
> >>>>>>Buffalo... the guy told me that was common practice in the north for
> >>>>
> >>>>rust
> >>>>
> >>>>
> >>>>>>prevention. Do they do that in Canada?
> >>>>>>
> >>>>>>JimG
> >>>>>>
> >>>>>>"twaldron" wrote in message ...
> >>>>>>
> >>>>>>
> >>>>>>>Here is my theory FWIW:
> >>>>>>>
> >>>>>>>The orig owner may have first passed on installing adj. control arms
> >>>>
> >>>>and
> >>>>
> >>>>
> >>>>>>>used the drop kit instead, thinking he was saving money. After
> >>>>>>>experiencing some driveline vibes even with the drop kit, he installed
> >>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms to
> >>>>>>>complete the job. Of course, I'm going on one photo that does not show
> >>>>>>>everything (including a drop kit) and a vivid imagination.
> >>>>>>>
> >>>>>>>So what of it, JimG...do you have any adj. upper control arms?
> >>>>>>>
> >>>>
> >>>>
> >>>>
> >>>--
> >>>_______________________________________________ ____________
> >>>tw
> >>>
> >>>71 Bill Stroppe Baja Bronco
> >>>03 TJ Rubicon - Rubicon Express 4.5"
> >>>01 XJ Sport
> >>>
> >>>There is a very fine line between "hobby" and "mental illness."
> >>>-- Dave Barry
> >>>
> >>>Pronunciation: 'jEp
> >>>Function: noun
> >>>Date: 1940
> >>>
> >>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> >>>A small general-purpose motor vehicle with 80-inch wheelbase,
> >>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
> >>>World War II.
> >>>
> >>>(Please remove the OBVIOUS to reply by email)
> >>>_______________________________________________ ____________

Peter Pontbriand

If you look at this photo again
http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG you'll see that the
t-case yoke is forward of the frame end of the stock control arms for the
rear axle. Same is true for the front, only even more pronounced.

/Peter

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4187DE1C.7CC24B10@sympatico.ca...
> I could be mistaken, but I don't buy your explanation at all.
>
> The driveshaft pivot is up high on the t-case. The control arm front
> pivot is low below the frame. The arc the lower arm describes will make
> the driveshaft extend as it goes down.
>
> It is the lower arc's lower center that will draw the driveshaft out.
>
> I will look real close next time I see a TJ hoisted, that's for sure.
> My curiosity is up.
>
> Mike
>
> Steve wrote:
> >
> > Hi Mike,
> >
> > Peter's right on that one. The TJ lower control arms are fixed to the
> > frame between the t-case and axle. In other words, the radius of the
> > control arm arc is shorter than the radius of the drive shaft arc. When
> > the axle drops on the control arm arc, it gets closer to the t-case and
> > compresses the drive shaft.
> >
> > By the way Peter, a lowered t-case will exaggerate the drive shaft
> > compression but the shaft will compress even with the t-case cross
> > member in the stock position.
> >
> > The upper arms pull the pinion angle down as the axle drops, so distance
> > from pinion to t-case is increased a tiny bit, but this is relatively
> > insignificant compared to the amount the distance is shortened as the
> > axle drops on the lower control arm arc.
> >
> > My front shaft definitely compresses when the axle is hanging fully
down.
> >
> > Steve
> > http://xjeep.dyndns.org
> >
> > Mike Romain wrote:
> > > The TJ has an upper and lower arm so the axle does indeed drop almost
> > > straight down. The gent's photos show an upper control arm.
> > >
> > > I know the spring still sits flat at full droop because I have helped
> > > replace them.
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > Peter Pontbriand wrote:
> > >
> > >>But, when the axle droops it doesn't drop straight down, it moves
though an
> > >>arc. The length of the control arms is fixed, so the whole axle
assembly
> > >>essentially pivots around the frame control arm mounts. Given that, if
the
> > >>transfer case output is lower than this pivot point, the driveshaft is
going
> > >>to compress.
> > >>
> > >>/Peter
> > >>
> > >>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> > >>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
> > >>
> > >>>No. Your pumpkin end is lower than your xfer case end. If you droop
the
> > >>>axle, it moves further away from the xfer case output shaft and
becomes
> > >>>longer.
> > >>>
> > >>>Peter Pontbriand wrote:
> > >>>
> > >>>
> > >>>>Full droop would shorten the drive shaft on a suspension like that,
> > >>
> > >>wouldn't
> > >>
> > >>>>it? I think the t-case output is lower than the frame-end control
arm
> > >>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ
is on
> > >>
> > >>a
> > >>
> > >>>>lift as compared to when it's sitting on it's wheels, even with the
> > >>
> > >>raised
> > >>
> > >>>>t-case skid.
> > >>>>
> > >>>>/Peter
> > >>>>
> > >>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
> > >>>>news:4187946D.85A9BF4B@sympatico.ca...
> > >>>>
> > >>>>
> > >>>>>The oil spray is common for rust protection.
> > >>>>>
> > >>>>>Your rear pinion angle looks almost right from the angle the photo
> > >>>>>shows. It is supposed to be pointing square at the driveshaft.
> > >>>>>
> > >>>>>If you jack up the rear of the Jeep and let the axle hang in space,
it
> > >>>>>can give you an idea if the axle is long enough. There is a spline
slip
> > >>>>>joint in the axle. If it is only say 1/4 the way out at full
droop,
> > >>>>>then likely you have tons of room to raise that plate back up where
it
> > >>>>>should be.
> > >>>>>
> > >>>>>While it's drooped you could at least unbolt the t-case end and
just
> > >>>>>hand place it up higher to see if it extends enough.
> > >>>>>
> > >>>>>Mike
> > >>>>>
> > >>>>>JimG wrote:
> > >>>>>
> > >>>>>
> > >>>>>>No adjustable control arms:
> > >>>>>>
> > >>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> > >>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> > >>>>>>
> > >>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was
from
> > >>>>>>Buffalo... the guy told me that was common practice in the north
for
> > >>>>
> > >>>>rust
> > >>>>
> > >>>>
> > >>>>>>prevention. Do they do that in Canada?
> > >>>>>>
> > >>>>>>JimG
> > >>>>>>
> > >>>>>>"twaldron" wrote in message ...
> > >>>>>>
> > >>>>>>
> > >>>>>>>Here is my theory FWIW:
> > >>>>>>>
> > >>>>>>>The orig owner may have first passed on installing adj. control
arms
> > >>>>
> > >>>>and
> > >>>>
> > >>>>
> > >>>>>>>used the drop kit instead, thinking he was saving money. After
> > >>>>>>>experiencing some driveline vibes even with the drop kit, he
installed
> > >>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms
to
> > >>>>>>>complete the job. Of course, I'm going on one photo that does not
show
> > >>>>>>>everything (including a drop kit) and a vivid imagination.
> > >>>>>>>
> > >>>>>>>So what of it, JimG...do you have any adj. upper control arms?
> > >>>>>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>--
> > >>>_______________________________________________ ____________
> > >>>tw
> > >>>
> > >>>71 Bill Stroppe Baja Bronco
> > >>>03 TJ Rubicon - Rubicon Express 4.5"
> > >>>01 XJ Sport
> > >>>
> > >>>There is a very fine line between "hobby" and "mental illness."
> > >>>-- Dave Barry
> > >>>
> > >>>Pronunciation: 'jEp
> > >>>Function: noun
> > >>>Date: 1940
> > >>>
> > >>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> > >>>A small general-purpose motor vehicle with 80-inch wheelbase,
> > >>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
> > >>>World War II.
> > >>>
> > >>>(Please remove the OBVIOUS to reply by email)
> > >>>_______________________________________________ ____________

Peter Pontbriand

If you look at this photo again
http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG you'll see that the
t-case yoke is forward of the frame end of the stock control arms for the
rear axle. Same is true for the front, only even more pronounced.

/Peter

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4187DE1C.7CC24B10@sympatico.ca...
> I could be mistaken, but I don't buy your explanation at all.
>
> The driveshaft pivot is up high on the t-case. The control arm front
> pivot is low below the frame. The arc the lower arm describes will make
> the driveshaft extend as it goes down.
>
> It is the lower arc's lower center that will draw the driveshaft out.
>
> I will look real close next time I see a TJ hoisted, that's for sure.
> My curiosity is up.
>
> Mike
>
> Steve wrote:
> >
> > Hi Mike,
> >
> > Peter's right on that one. The TJ lower control arms are fixed to the
> > frame between the t-case and axle. In other words, the radius of the
> > control arm arc is shorter than the radius of the drive shaft arc. When
> > the axle drops on the control arm arc, it gets closer to the t-case and
> > compresses the drive shaft.
> >
> > By the way Peter, a lowered t-case will exaggerate the drive shaft
> > compression but the shaft will compress even with the t-case cross
> > member in the stock position.
> >
> > The upper arms pull the pinion angle down as the axle drops, so distance
> > from pinion to t-case is increased a tiny bit, but this is relatively
> > insignificant compared to the amount the distance is shortened as the
> > axle drops on the lower control arm arc.
> >
> > My front shaft definitely compresses when the axle is hanging fully
down.
> >
> > Steve
> > http://xjeep.dyndns.org
> >
> > Mike Romain wrote:
> > > The TJ has an upper and lower arm so the axle does indeed drop almost
> > > straight down. The gent's photos show an upper control arm.
> > >
> > > I know the spring still sits flat at full droop because I have helped
> > > replace them.
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > Peter Pontbriand wrote:
> > >
> > >>But, when the axle droops it doesn't drop straight down, it moves
though an
> > >>arc. The length of the control arms is fixed, so the whole axle
assembly
> > >>essentially pivots around the frame control arm mounts. Given that, if
the
> > >>transfer case output is lower than this pivot point, the driveshaft is
going
> > >>to compress.
> > >>
> > >>/Peter
> > >>
> > >>"twaldron" <thomas@OBVIOUSrubicons.com> wrote in message
> > >>news:6pOhd.14801$bP2.8253@newssvr12.news.prodigy .com...
> > >>
> > >>>No. Your pumpkin end is lower than your xfer case end. If you droop
the
> > >>>axle, it moves further away from the xfer case output shaft and
becomes
> > >>>longer.
> > >>>
> > >>>Peter Pontbriand wrote:
> > >>>
> > >>>
> > >>>>Full droop would shorten the drive shaft on a suspension like that,
> > >>
> > >>wouldn't
> > >>
> > >>>>it? I think the t-case output is lower than the frame-end control
arm
> > >>>>mounts. I'm pretty sure my drive shafts are compressed when the TJ
is on
> > >>
> > >>a
> > >>
> > >>>>lift as compared to when it's sitting on it's wheels, even with the
> > >>
> > >>raised
> > >>
> > >>>>t-case skid.
> > >>>>
> > >>>>/Peter
> > >>>>
> > >>>>"Mike Romain" <romainm@sympatico.ca> wrote in message
> > >>>>news:4187946D.85A9BF4B@sympatico.ca...
> > >>>>
> > >>>>
> > >>>>>The oil spray is common for rust protection.
> > >>>>>
> > >>>>>Your rear pinion angle looks almost right from the angle the photo
> > >>>>>shows. It is supposed to be pointing square at the driveshaft.
> > >>>>>
> > >>>>>If you jack up the rear of the Jeep and let the axle hang in space,
it
> > >>>>>can give you an idea if the axle is long enough. There is a spline
slip
> > >>>>>joint in the axle. If it is only say 1/4 the way out at full
droop,
> > >>>>>then likely you have tons of room to raise that plate back up where
it
> > >>>>>should be.
> > >>>>>
> > >>>>>While it's drooped you could at least unbolt the t-case end and
just
> > >>>>>hand place it up higher to see if it extends enough.
> > >>>>>
> > >>>>>Mike
> > >>>>>
> > >>>>>JimG wrote:
> > >>>>>
> > >>>>>
> > >>>>>>No adjustable control arms:
> > >>>>>>
> > >>>>>>http://www.citlink.net/~gunnoes/Photos/LowerKit.JPG
> > >>>>>>http://www.citlink.net/~gunnoes/Photos/RearAxle.JPG
> > >>>>>>
> > >>>>>>Hey Mike... notice the oil sprayed under there? This Jeep was
from
> > >>>>>>Buffalo... the guy told me that was common practice in the north
for
> > >>>>
> > >>>>rust
> > >>>>
> > >>>>
> > >>>>>>prevention. Do they do that in Canada?
> > >>>>>>
> > >>>>>>JimG
> > >>>>>>
> > >>>>>>"twaldron" wrote in message ...
> > >>>>>>
> > >>>>>>
> > >>>>>>>Here is my theory FWIW:
> > >>>>>>>
> > >>>>>>>The orig owner may have first passed on installing adj. control
arms
> > >>>>
> > >>>>and
> > >>>>
> > >>>>
> > >>>>>>>used the drop kit instead, thinking he was saving money. After
> > >>>>>>>experiencing some driveline vibes even with the drop kit, he
installed
> > >>>>>>>the CV driveshaft. JimG might have to buy some adj. control arms
to
> > >>>>>>>complete the job. Of course, I'm going on one photo that does not
show
> > >>>>>>>everything (including a drop kit) and a vivid imagination.
> > >>>>>>>
> > >>>>>>>So what of it, JimG...do you have any adj. upper control arms?
> > >>>>>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>--
> > >>>_______________________________________________ ____________
> > >>>tw
> > >>>
> > >>>71 Bill Stroppe Baja Bronco
> > >>>03 TJ Rubicon - Rubicon Express 4.5"
> > >>>01 XJ Sport
> > >>>
> > >>>There is a very fine line between "hobby" and "mental illness."
> > >>>-- Dave Barry
> > >>>
> > >>>Pronunciation: 'jEp
> > >>>Function: noun
> > >>>Date: 1940
> > >>>
> > >>>Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
> > >>>A small general-purpose motor vehicle with 80-inch wheelbase,
> > >>>1/4-ton capacity, and four-wheel drive used by the U.S. army in
> > >>>World War II.
> > >>>
> > >>>(Please remove the OBVIOUS to reply by email)
> > >>>_______________________________________________ ____________