My cousin Zach has a 96 GC with the 4.0 and automatic.
his rearend was leaking and i helped him replace the seal and it stopped. He filled up the rear and left for college. His rear caught on fire and smoke to beat the band.

He said it is now so load he cant listen to the radio.
Is it difficult to rebuild the rear ?
he is having it puled to my shop so I can pull the cover off and see what happened.

 

what seal did you replace? Rebuilding a rearend is a pretty in depth job. The pinion gear and ring gear have to mesh perfectly or you will ruin them. THe pinion bearing preload has to be set corectly as well of it will fail. If you replaced teh pinion seal I would guess you did not get it back to the correct preload and you destroyed teh bearing and probably the pinion.

Please tell us which seal you repalced.

 

The yoke seal.
I think i torqued it to about 250 lb foot. just kidding, snugged it up so not to overtighten it.

 

Forget rebuilding it. Find another one that matches the previous one and just swap it in. Much cheaper and quicker.

 

Kyle, I just got done talking to a friend who said the same thing. Replace it, whole lot cheaper than rebuilding it.

 

then it was probably too loose. at a minimum you needed to mark the threads and get back to that plus about 5 ft lbs. THe correct way to do it is to measure the force to rotate it in in lbs then retorque it back to that plus 5 ft lbs. I would guess you destroyed teh pinion bearing and maybe even the pinion, as mentioned probably easier to get a whole unit from the scrap yard.

 

you can't measure the bearing preload in in/lb of turning force when the carrier is installed. that only works when you're rebuilding, and only the pinion gear is installed, before the rest goes in. and its measured in in/lb, not ft/lb. 5 ft/lb of turning force on the pinion would destroy it, the spec is around 30 in/lb when using new bearings. but i do think you mean retorquing it a little harder than before when reinstalling the yoke, which is ok i guess, the crush sleeve is crushed where it should be. honestly though, i've replaced hundreds of pinion seals, and all you have to do is replace the seal, and technically you are not supposed to reuse the pinion nut, but you can get away with it if you use a little thread locker. and just tighten the nut down good and tight with an impact gun. the preload is already set, just try not to make it any tighter by rapping on it for a minute or something. it is possible that the nut worked loose, i have seen it before when re using the nut, then it could've caused damage. see if the yoke is loose.

replacing ring and pinion and all bearings is doable, but it does take skill, and a few special tools. actually i probably have about 2 grand in rear end tools, plus you need a press. its a good skill to learn, but you need to learn from someone who knows how to do it.

take pics or let us know what it looks like, hope that helps.

 

and yes, some manuals give you an actual torque spec when reinstalling the nut after preload has already been set. and it is like 250 lb/ft. but that method sucks.

 

I hear ya.
His yoke wasnt loose. It was on tight and used a breaker bar to get it loose.

We pulled the rear cover off and the gears are moving in and out a little.
i reckon the bearings are shot. Gears looked fine.
Maybe just replace the main bearings ?

 

well replacing bearings is easy. just replace them all while you're there. the only special tool you need is an in/lb dial indicator torque wrench. it gets more complicated when replacing the ring and pinion. just put the carrier shims back where they came from. there's a shim under the innner pinion bearing, make sure you reuse that also.

 

in my experience if you start replacing bearing you need to at least recheck all of the clearances, the end play, the pinion bearing preload and the gear pattern between the pinion and teh ring. I would get a master rebuild kit and if you do not have the tools or the ability to do it yourself hire someone to do it. That will probably cost more than a salvage yard swap as suggested earlier.

From my FSM
NOTE: If differential side bearings or differential
case are replaced, differential side bearing shim
requirements may change. Refer to Adjustments
(Differential Bearing Preload and Gear Backlash) for
procedures.