Rear Diff seal
 

Ok so I replaced the rear diff gasket on the back cover and refilled it with the recommended gear oil and I'm noticing that since it's full it looks like I have a leak on the front seal where the shaft comes out and connects to the driveshaft. How hard is it to replace this seal.... do I have to tear the entire thing apart or can I take the universal loose and get that front shaft out of the rearend without breakin' the whole thing down??

RE: Rear Diff seal
 

Boy... That's a difficult one. I know that in the past we have taken and replaced the front seal on some of our farm trucks by removing the front yoke, popping in a new seal, and just tightening it back down to spec. But that was on our farm trucks that never really got to see a lot of highway.

The problem comes in if you end up crushing the crush sleave more when you tighten down the retaining nut for the yoke. That will throw off your gear engagement...

RE: Rear Diff seal
 

yes you can do it but its tricky.
you have to drop the driveshaft and use a socket to remove the pinion gear nut. pry out the old seal, install the new. retorque the pinion gear nut. you should be okay as long as you tighten the nut slowly until there is no in-out play in the pinion gear. the nut should be in about the same position as it was before.

if you have a torque wrench you can torque to spec, but any time ive done it or seen it done it has been done by a careful hand w/ no torque wrench involved.

RE: Rear Diff seal
 

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RE: Rear Diff seal
 

The suggested way to do this is to first measure the pinion preload. With a guage type torque wrench turn the pinion nut (after the driveshaft is removed and the rear wheels in the air turning freely.
Record this measurement and recheck preload after repair( and frequently as you tighten the pinion nut on final assembly)







Remove the rear driveshaft. Take a center punch and mark the pinion nut and the pinion shaft. Remove the nut, washer and yolk. Then with a screwdriver and hammer, remove the seal. clean out the front of the diff where the new seal goes in.
It's a little tricky installing the new seal flat without a seal installer because of the pinion shaft, but it still can be done.
before you install the new seal, put a coating of pipe thread sealant on to outer surface (the part that will be in contact with the diff housing. Put a little wheel bearing grease on the inner seal surface. Put the seal into place and then with a piece of 2x4 and a hammer gently work the seal into place. Just keep moving around the seal so you don't distort the shape.
Put a layer of pipe thread sealant on the splines inside the yolk before you install it.
Then install the yolk ( a little persuading with a hammer) til it seats. then install the the washer and locknut.
Tighten the nut til you get close to the torque measurement that you recorded before you took it apart and keep an eye on the punch marks that you made for a reference (you should wind up close to lining up the punch marks.

If you have the tools and take your time, it works ok.

Make sure your parking brake works well before you start because you will have to apply a lot of tourqe to the pinion nut and you don't want the rear wheels turning on you.


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RE: Rear Diff seal
 

heh.. yeah... I wonder how many people have said.. "Oh I'll just put it in park".........:\

Kewl... don't sound too bad... one of those "time consuming" but not so much tough jobs. for now I'mma just make sure it stays topped off under there and then I'll be doin' it soon enough. Guess I'll go ahead and order the part and put it on the dash so it'll haunt me until I do it....:P


thx for the info folks....;)