Jerry Bransford

"Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
news:3ff1c091@rutgers.edu...
> I don't have a Rubicon but there are two possible issues. The NP242 on
> the Rubicon has a fixed yoke rear output already so the 'usual'
> slip-yoke induced vibration problems on the NP241 wouldn't become an
issue.

Tim, it's not the slip yoke itself that causes vibrations, it's only the
driveshaft angle that does. That the Rubicon has moved the slip yoke to the
driveshaft doesn't change the lift height that will cause drivetrain
vibrations. That the Rubicon has a slightly longer driveshaft due to the
elimination of the t-case slip yoke will help though. :)

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.***.net/jerrypb/
>
> The first 'maybe' is driveshaft length. With the t-case and suspesion
> lifts you might over-extend it if you fully articulate the rear. I'm
> sure it would be fine on the road, but under full articulation on the
> trail it could have insufficient contact in the slip joint which might
> damage it under high torque (or even cause it to fall out!)
>
> Second, it is possible that the increased angle of the u-joints with the
> lift could be too large for them to operate correctly. They could break
> if the angle is too large (again- under full articulation.) You might
> need a double-cardan CV shaft or a special high-angle shaft.
>
> Do your lifts and jack up the back. See how things look and decide from
> there. But don't take it off-road until you check it out or someone with
> more knowledge then I gives you a better answer!
>
> Andrew wrote:
>
> > I have an 03 TJ Rubicon, and will put in a 2" Old Man Emu suspension
> > lift and also run 1.5" engine lift (and body) to fit a high clearance
> > skidplate. What driveline problems should I expect, what do I need to
> > buy in advance to fix the problems, how do I fix it, and will I need
> > to have custom driveshafts made?
> >
> > Thanks for your time and help,
> >
> > Andrew Whitley
>

Jerry Bransford

"Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
news:3ff1c091@rutgers.edu...
> I don't have a Rubicon but there are two possible issues. The NP242 on
> the Rubicon has a fixed yoke rear output already so the 'usual'
> slip-yoke induced vibration problems on the NP241 wouldn't become an
issue.

Tim, it's not the slip yoke itself that causes vibrations, it's only the
driveshaft angle that does. That the Rubicon has moved the slip yoke to the
driveshaft doesn't change the lift height that will cause drivetrain
vibrations. That the Rubicon has a slightly longer driveshaft due to the
elimination of the t-case slip yoke will help though. :)

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.***.net/jerrypb/
>
> The first 'maybe' is driveshaft length. With the t-case and suspesion
> lifts you might over-extend it if you fully articulate the rear. I'm
> sure it would be fine on the road, but under full articulation on the
> trail it could have insufficient contact in the slip joint which might
> damage it under high torque (or even cause it to fall out!)
>
> Second, it is possible that the increased angle of the u-joints with the
> lift could be too large for them to operate correctly. They could break
> if the angle is too large (again- under full articulation.) You might
> need a double-cardan CV shaft or a special high-angle shaft.
>
> Do your lifts and jack up the back. See how things look and decide from
> there. But don't take it off-road until you check it out or someone with
> more knowledge then I gives you a better answer!
>
> Andrew wrote:
>
> > I have an 03 TJ Rubicon, and will put in a 2" Old Man Emu suspension
> > lift and also run 1.5" engine lift (and body) to fit a high clearance
> > skidplate. What driveline problems should I expect, what do I need to
> > buy in advance to fix the problems, how do I fix it, and will I need
> > to have custom driveshafts made?
> >
> > Thanks for your time and help,
> >
> > Andrew Whitley
>

Jerry Bransford

"Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
news:3ff1c091@rutgers.edu...
> I don't have a Rubicon but there are two possible issues. The NP242 on
> the Rubicon has a fixed yoke rear output already so the 'usual'
> slip-yoke induced vibration problems on the NP241 wouldn't become an
issue.

Tim, it's not the slip yoke itself that causes vibrations, it's only the
driveshaft angle that does. That the Rubicon has moved the slip yoke to the
driveshaft doesn't change the lift height that will cause drivetrain
vibrations. That the Rubicon has a slightly longer driveshaft due to the
elimination of the t-case slip yoke will help though. :)

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.***.net/jerrypb/
>
> The first 'maybe' is driveshaft length. With the t-case and suspesion
> lifts you might over-extend it if you fully articulate the rear. I'm
> sure it would be fine on the road, but under full articulation on the
> trail it could have insufficient contact in the slip joint which might
> damage it under high torque (or even cause it to fall out!)
>
> Second, it is possible that the increased angle of the u-joints with the
> lift could be too large for them to operate correctly. They could break
> if the angle is too large (again- under full articulation.) You might
> need a double-cardan CV shaft or a special high-angle shaft.
>
> Do your lifts and jack up the back. See how things look and decide from
> there. But don't take it off-road until you check it out or someone with
> more knowledge then I gives you a better answer!
>
> Andrew wrote:
>
> > I have an 03 TJ Rubicon, and will put in a 2" Old Man Emu suspension
> > lift and also run 1.5" engine lift (and body) to fit a high clearance
> > skidplate. What driveline problems should I expect, what do I need to
> > buy in advance to fix the problems, how do I fix it, and will I need
> > to have custom driveshafts made?
> >
> > Thanks for your time and help,
> >
> > Andrew Whitley
>

twaldron

I can attest to that, Jerry. We lifted two Rubis (autos) 4.5" and both
had driveline vibes before the Tom Woods CV shaft kits. It _might_ have
been possible to tune out the vibes with just the control arms (I doubt
it though), but the driveshaft would have been too short anyway.

In a small way, the slip yoke does contribute to the vibes in that it
effectively shortens an already short shaft somewhat. The slip yoke
eliminator kit lengthens the main shaft which will help eliminate vibes.
The difference is probably minute, but every bit helps. The main thing
you need to do is change the driveshaft attitude to eliminate them
completely.

Jerry Bransford wrote:

> "Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
> news:3ff1c091@rutgers.edu...
>
>>I don't have a Rubicon but there are two possible issues. The NP242 on
>>the Rubicon has a fixed yoke rear output already so the 'usual'
>>slip-yoke induced vibration problems on the NP241 wouldn't become an
>
> issue.
>
> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)
>
> Jerry

--
__________________________________________________ _________
tw
03 TJ Rubicon
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: probably from g. p. (abbreviation of general purpose)
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.

http://www.7slotgrille.com/jeepers/t...ron/index.html
(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________

twaldron

I can attest to that, Jerry. We lifted two Rubis (autos) 4.5" and both
had driveline vibes before the Tom Woods CV shaft kits. It _might_ have
been possible to tune out the vibes with just the control arms (I doubt
it though), but the driveshaft would have been too short anyway.

In a small way, the slip yoke does contribute to the vibes in that it
effectively shortens an already short shaft somewhat. The slip yoke
eliminator kit lengthens the main shaft which will help eliminate vibes.
The difference is probably minute, but every bit helps. The main thing
you need to do is change the driveshaft attitude to eliminate them
completely.

Jerry Bransford wrote:

> "Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
> news:3ff1c091@rutgers.edu...
>
>>I don't have a Rubicon but there are two possible issues. The NP242 on
>>the Rubicon has a fixed yoke rear output already so the 'usual'
>>slip-yoke induced vibration problems on the NP241 wouldn't become an
>
> issue.
>
> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)
>
> Jerry

--
__________________________________________________ _________
tw
03 TJ Rubicon
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: probably from g. p. (abbreviation of general purpose)
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.

http://www.7slotgrille.com/jeepers/t...ron/index.html
(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________

twaldron

I can attest to that, Jerry. We lifted two Rubis (autos) 4.5" and both
had driveline vibes before the Tom Woods CV shaft kits. It _might_ have
been possible to tune out the vibes with just the control arms (I doubt
it though), but the driveshaft would have been too short anyway.

In a small way, the slip yoke does contribute to the vibes in that it
effectively shortens an already short shaft somewhat. The slip yoke
eliminator kit lengthens the main shaft which will help eliminate vibes.
The difference is probably minute, but every bit helps. The main thing
you need to do is change the driveshaft attitude to eliminate them
completely.

Jerry Bransford wrote:

> "Tim Hayes" <thayes@remove-me.rutgers.edu> wrote in message
> news:3ff1c091@rutgers.edu...
>
>>I don't have a Rubicon but there are two possible issues. The NP242 on
>>the Rubicon has a fixed yoke rear output already so the 'usual'
>>slip-yoke induced vibration problems on the NP241 wouldn't become an
>
> issue.
>
> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)
>
> Jerry

--
__________________________________________________ _________
tw
03 TJ Rubicon
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: probably from g. p. (abbreviation of general purpose)
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.

http://www.7slotgrille.com/jeepers/t...ron/index.html
(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________

Tim Hayes

Isn't the angle only an issue in two ways?

1) a u-joint has a maximum angle it can operate through

2) the angle on both ends of a 2 u-joint driveshaft must be the same

Since a stock TJ doesn't have a second u-joint won't you always violate
#2 except at one specific ride height (and even then whenever you flex
over a bump)?

Couldn't you correct #2 by adding the second u-joint without lengthening
the driveshaft provided you don't violate #1?

This is all from my mechanical engineering classed in college so maybe
I've got it wrong. It isn't like i've ever actually built a drivetrain
myself, but I thought I understood the theory pretty well.

Jerry Bransford wrote:

> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)

Tim Hayes

Isn't the angle only an issue in two ways?

1) a u-joint has a maximum angle it can operate through

2) the angle on both ends of a 2 u-joint driveshaft must be the same

Since a stock TJ doesn't have a second u-joint won't you always violate
#2 except at one specific ride height (and even then whenever you flex
over a bump)?

Couldn't you correct #2 by adding the second u-joint without lengthening
the driveshaft provided you don't violate #1?

This is all from my mechanical engineering classed in college so maybe
I've got it wrong. It isn't like i've ever actually built a drivetrain
myself, but I thought I understood the theory pretty well.

Jerry Bransford wrote:

> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)

Tim Hayes

Isn't the angle only an issue in two ways?

1) a u-joint has a maximum angle it can operate through

2) the angle on both ends of a 2 u-joint driveshaft must be the same

Since a stock TJ doesn't have a second u-joint won't you always violate
#2 except at one specific ride height (and even then whenever you flex
over a bump)?

Couldn't you correct #2 by adding the second u-joint without lengthening
the driveshaft provided you don't violate #1?

This is all from my mechanical engineering classed in college so maybe
I've got it wrong. It isn't like i've ever actually built a drivetrain
myself, but I thought I understood the theory pretty well.

Jerry Bransford wrote:

> Tim, it's not the slip yoke itself that causes vibrations, it's only the
> driveshaft angle that does. That the Rubicon has moved the slip yoke to the
> driveshaft doesn't change the lift height that will cause drivetrain
> vibrations. That the Rubicon has a slightly longer driveshaft due to the
> elimination of the t-case slip yoke will help though. :)

L.W.(=?iso-8859-1?Q?=DFill?=) Hughes III

Hi Tim,
Yes, the Constant Velocity will also allow a greater angle, so Real
Jeep may clock their transfer cases up higher out of harms way. And
allow you to aim the differential pinion straight at the higher transfer
yoke: http://www.4xshaft.com/driveline101.html
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/


Tim Hayes wrote:
>
> Isn't the angle only an issue in two ways?
>
> 1) a u-joint has a maximum angle it can operate through
>
> 2) the angle on both ends of a 2 u-joint driveshaft must be the same
>
> Since a stock TJ doesn't have a second u-joint won't you always violate
> #2 except at one specific ride height (and even then whenever you flex
> over a bump)?
>
> Couldn't you correct #2 by adding the second u-joint without lengthening
> the driveshaft provided you don't violate #1?
>
> This is all from my mechanical engineering classed in college so maybe
> I've got it wrong. It isn't like i've ever actually built a drivetrain
> myself, but I thought I understood the theory pretty well.