Guest

Can you replace the rear main seal on a 91 4.0 YJ automatic without removing
the engine? If so, what is involved.

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Gerald G. McGeorge

Yes. You must drain the oil & remove the oil pan, then remove the rear main
bearing cap & bearing. You then GENTLY push out the old upper seal half and
reinstall a replacement. Remove the old lower seal half at the rear of the
rear main bearing cap, install the new lower seal half , torque the main
bearing cap in several steps to the factory torque, reinstall the pan with a
new gasket, torque all pan bolts evenly and you're done.....But wait,
there's more!

What leaks as often as the seal is the pan gasket at the rear main bearing
cap. When you reinstall a new pan gasket get the one piece unit sold by the
dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
main seal where the pan gasket seats, plus put some on the pan surface all
along the rear of the pan, opposite the rear main bearing cap. Be sure to
install the gasket FIRST, holding it in place with a few studs in the oil
pan bolt holes (these keep it in place while you install the pan. If you do
all this, and if you didn't FU the new seal putting it in, the fix will last
about 25k - 40k miles before it starts to leak again. Live with it, it's
part of owning an old Jeep!


<rorr4@cfl.rr.com> wrote in message
news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> Can you replace the rear main seal on a 91 4.0 YJ automatic without
removing
> the engine? If so, what is involved.
>
> --
> -----------------------------------------------------
> Click here for Free Video!!
> http://www.gohip.com/free_video/
>
>

Gerald G. McGeorge

Yes. You must drain the oil & remove the oil pan, then remove the rear main
bearing cap & bearing. You then GENTLY push out the old upper seal half and
reinstall a replacement. Remove the old lower seal half at the rear of the
rear main bearing cap, install the new lower seal half , torque the main
bearing cap in several steps to the factory torque, reinstall the pan with a
new gasket, torque all pan bolts evenly and you're done.....But wait,
there's more!

What leaks as often as the seal is the pan gasket at the rear main bearing
cap. When you reinstall a new pan gasket get the one piece unit sold by the
dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
main seal where the pan gasket seats, plus put some on the pan surface all
along the rear of the pan, opposite the rear main bearing cap. Be sure to
install the gasket FIRST, holding it in place with a few studs in the oil
pan bolt holes (these keep it in place while you install the pan. If you do
all this, and if you didn't FU the new seal putting it in, the fix will last
about 25k - 40k miles before it starts to leak again. Live with it, it's
part of owning an old Jeep!


<rorr4@cfl.rr.com> wrote in message
news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> Can you replace the rear main seal on a 91 4.0 YJ automatic without
removing
> the engine? If so, what is involved.
>
> --
> -----------------------------------------------------
> Click here for Free Video!!
> http://www.gohip.com/free_video/
>
>

Kevin in San Diego

Also if you have never had the oil pan off, the original gasket is a major
pain in the rear to clean up and get off. Prepare to spend a LOT of time
getting it cleaned off.
KH

"Gerald G. McGeorge" <gmcgeorge@frontier.net> wrote in message
news:vmsi6utnka44ab@corp.supernews.com...
> Yes. You must drain the oil & remove the oil pan, then remove the rear
main
> bearing cap & bearing. You then GENTLY push out the old upper seal half
and
> reinstall a replacement. Remove the old lower seal half at the rear of the
> rear main bearing cap, install the new lower seal half , torque the main
> bearing cap in several steps to the factory torque, reinstall the pan with
a
> new gasket, torque all pan bolts evenly and you're done.....But wait,
> there's more!
>
> What leaks as often as the seal is the pan gasket at the rear main bearing
> cap. When you reinstall a new pan gasket get the one piece unit sold by
the
> dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
> main seal where the pan gasket seats, plus put some on the pan surface all
> along the rear of the pan, opposite the rear main bearing cap. Be sure to
> install the gasket FIRST, holding it in place with a few studs in the oil
> pan bolt holes (these keep it in place while you install the pan. If you
do
> all this, and if you didn't FU the new seal putting it in, the fix will
last
> about 25k - 40k miles before it starts to leak again. Live with it, it's
> part of owning an old Jeep!
>
>
> <rorr4@cfl.rr.com> wrote in message
> news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> > Can you replace the rear main seal on a 91 4.0 YJ automatic without
> removing
> > the engine? If so, what is involved.
> >
> > --
> > -----------------------------------------------------
> > Click here for Free Video!!
> > http://www.gohip.com/free_video/
> >
> >
>
>

Kevin in San Diego

Also if you have never had the oil pan off, the original gasket is a major
pain in the rear to clean up and get off. Prepare to spend a LOT of time
getting it cleaned off.
KH

"Gerald G. McGeorge" <gmcgeorge@frontier.net> wrote in message
news:vmsi6utnka44ab@corp.supernews.com...
> Yes. You must drain the oil & remove the oil pan, then remove the rear
main
> bearing cap & bearing. You then GENTLY push out the old upper seal half
and
> reinstall a replacement. Remove the old lower seal half at the rear of the
> rear main bearing cap, install the new lower seal half , torque the main
> bearing cap in several steps to the factory torque, reinstall the pan with
a
> new gasket, torque all pan bolts evenly and you're done.....But wait,
> there's more!
>
> What leaks as often as the seal is the pan gasket at the rear main bearing
> cap. When you reinstall a new pan gasket get the one piece unit sold by
the
> dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
> main seal where the pan gasket seats, plus put some on the pan surface all
> along the rear of the pan, opposite the rear main bearing cap. Be sure to
> install the gasket FIRST, holding it in place with a few studs in the oil
> pan bolt holes (these keep it in place while you install the pan. If you
do
> all this, and if you didn't FU the new seal putting it in, the fix will
last
> about 25k - 40k miles before it starts to leak again. Live with it, it's
> part of owning an old Jeep!
>
>
> <rorr4@cfl.rr.com> wrote in message
> news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> > Can you replace the rear main seal on a 91 4.0 YJ automatic without
> removing
> > the engine? If so, what is involved.
> >
> > --
> > -----------------------------------------------------
> > Click here for Free Video!!
> > http://www.gohip.com/free_video/
> >
> >
>
>

MudPuppy1976

remove the transmission and the flywheel, it's lighter than an engine
and there's less stuff to unplug
--
Ben Jerew
ASE Master Technician
New Country Lexus of Latham, NY
Amateur Off-Roader

MudPuppy1976

remove the transmission and the flywheel, it's lighter than an engine
and there's less stuff to unplug
--
Ben Jerew
ASE Master Technician
New Country Lexus of Latham, NY
Amateur Off-Roader

Will Honea

Either you're a real optimist or the luckiest guy around, unless
your'e definition of GENTLY is a whole lot different than mine! Mine
took a brass drift and a 4 pound hammer on top of lots of cussing to
break that top half-seal loose! Of course this was an '88 but a '91
has had time to cook in, too.

Just be sure you get a brass drift punch - welding rod or a stick of
brass from the hardware store just a little under a quarter inch will
do - so you don't bugger the crank surface. It also helps to loosen
the main bearing caps a bit but be sure you support the tranny on a
jack to keep stress off the crank. You need to use a small amount of
silicone sealer on the rear bearing cap ends of the seals so that they
mate right - see the shop manual and I think even the Haynes manual
mentions this.

Besides getting the pan off (it grows on, too) you will need to pull
the starter for working clearance. The first time I had the pan off I
spent a lot more time getting the old gasket scraped off than the rest
of the job combined, including the time it took to finally bang the
upper half of the seal out.

A little research will also make the job of getting the pan seal back
in place a lot easier. I personally use a thin layer of silicone both
to help the seal as well as to tack it up on the block while I lift
the pan. Just be careful as you put the bolts in - the silicone makes
the gasket slip around pretty easily, so get all the bolts started
before you start to tighten any of them. Replacing the seal is
actually the easiest part of the process.

On Mon, 22 Sep 2003 00:54:51 UTC "Gerald G. McGeorge"
<gmcgeorge@frontier.net> wrote:

> Yes. You must drain the oil & remove the oil pan, then remove the rear main
> bearing cap & bearing. You then GENTLY push out the old upper seal half and
> reinstall a replacement. Remove the old lower seal half at the rear of the
> rear main bearing cap, install the new lower seal half , torque the main
> bearing cap in several steps to the factory torque, reinstall the pan with a
> new gasket, torque all pan bolts evenly and you're done.....But wait,
> there's more!
>
> What leaks as often as the seal is the pan gasket at the rear main bearing
> cap. When you reinstall a new pan gasket get the one piece unit sold by the
> dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
> main seal where the pan gasket seats, plus put some on the pan surface all
> along the rear of the pan, opposite the rear main bearing cap. Be sure to
> install the gasket FIRST, holding it in place with a few studs in the oil
> pan bolt holes (these keep it in place while you install the pan. If you do
> all this, and if you didn't FU the new seal putting it in, the fix will last
> about 25k - 40k miles before it starts to leak again. Live with it, it's
> part of owning an old Jeep!
>
>
> <rorr4@cfl.rr.com> wrote in message
> news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> > Can you replace the rear main seal on a 91 4.0 YJ automatic without
> removing
> > the engine? If so, what is involved.
> >
> > --
> > -----------------------------------------------------
> > Click here for Free Video!!
> > http://www.gohip.com/free_video/
> >
> >
>
>

Will Honea

Either you're a real optimist or the luckiest guy around, unless
your'e definition of GENTLY is a whole lot different than mine! Mine
took a brass drift and a 4 pound hammer on top of lots of cussing to
break that top half-seal loose! Of course this was an '88 but a '91
has had time to cook in, too.

Just be sure you get a brass drift punch - welding rod or a stick of
brass from the hardware store just a little under a quarter inch will
do - so you don't bugger the crank surface. It also helps to loosen
the main bearing caps a bit but be sure you support the tranny on a
jack to keep stress off the crank. You need to use a small amount of
silicone sealer on the rear bearing cap ends of the seals so that they
mate right - see the shop manual and I think even the Haynes manual
mentions this.

Besides getting the pan off (it grows on, too) you will need to pull
the starter for working clearance. The first time I had the pan off I
spent a lot more time getting the old gasket scraped off than the rest
of the job combined, including the time it took to finally bang the
upper half of the seal out.

A little research will also make the job of getting the pan seal back
in place a lot easier. I personally use a thin layer of silicone both
to help the seal as well as to tack it up on the block while I lift
the pan. Just be careful as you put the bolts in - the silicone makes
the gasket slip around pretty easily, so get all the bolts started
before you start to tighten any of them. Replacing the seal is
actually the easiest part of the process.

On Mon, 22 Sep 2003 00:54:51 UTC "Gerald G. McGeorge"
<gmcgeorge@frontier.net> wrote:

> Yes. You must drain the oil & remove the oil pan, then remove the rear main
> bearing cap & bearing. You then GENTLY push out the old upper seal half and
> reinstall a replacement. Remove the old lower seal half at the rear of the
> rear main bearing cap, install the new lower seal half , torque the main
> bearing cap in several steps to the factory torque, reinstall the pan with a
> new gasket, torque all pan bolts evenly and you're done.....But wait,
> there's more!
>
> What leaks as often as the seal is the pan gasket at the rear main bearing
> cap. When you reinstall a new pan gasket get the one piece unit sold by the
> dealer (it's gray rubber.), put a good RTV bead on the groove in the rear
> main seal where the pan gasket seats, plus put some on the pan surface all
> along the rear of the pan, opposite the rear main bearing cap. Be sure to
> install the gasket FIRST, holding it in place with a few studs in the oil
> pan bolt holes (these keep it in place while you install the pan. If you do
> all this, and if you didn't FU the new seal putting it in, the fix will last
> about 25k - 40k miles before it starts to leak again. Live with it, it's
> part of owning an old Jeep!
>
>
> <rorr4@cfl.rr.com> wrote in message
> news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
> > Can you replace the rear main seal on a 91 4.0 YJ automatic without
> removing
> > the engine? If so, what is involved.
> >
> > --
> > -----------------------------------------------------
> > Click here for Free Video!!
> > http://www.gohip.com/free_video/
> >
> >
>
>

Dave Milne

http://jeepin.com/features/rearmain/index.asp


Dave Milne, Scotland
'99 TJ 4.0 Sahara

<rorr4@cfl.rr.com> wrote in message
news:1lrbb.18767$Qd.704863@twister.tampabay.rr.com ...
: Can you replace the rear main seal on a 91 4.0 YJ automatic without
removing
: the engine? If so, what is involved.
:
: --
: -----------------------------------------------------
: Click here for Free Video!!
: http://www.gohip.com/free_video/
:
: