Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

So I'll be changing out a leaking pinion seal this weekend. I found THIS post:
I bought a new(to me) 10 bolt with a 3.42 torsen takeout from a 4th gen. Was set up by a local shop and it was in the shop owner's 91z. I don't know the years of which parts were used. Any quick tell or do I just need to poke and hope? They're not super expensive.... I could just buy 'em both.

FYI....just ordered one of each from the Advance. $37 bucks. I'll return one.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

That info came from me. Easiest way would probably be to just measure the diameter of the pinion shaft. I don't know the measurements off the top of my head, but I'm sure they could be found online with the p/n's of the seals.

BTW, I got my seal from the dealership.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Yes sir, thank you. I thought the quote cited it as being yours. I see it does not.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

I asked the counter guy if the seals were listed by diameter and he said he didn't have a dimension listed. Figured I'd just get 'em both and potentially save a trip while I'm wrenching.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

For the cost, that was a smart move. You can always return the unused one when you're done. Beats running back and forth trying to get the right one.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

8610 worked. ...I'll get the actual measurement of the pinion later.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Pinion measured 1.525"

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

I swapped out the pinion seal once on my 92 rs with open diff before I upgraded to a torsen. Started howling shortly after that and didn't fix the leak. My guest is if its leaking its not the seal its something else out of whack.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Torsen/rear has about 40k miles on it and has been sitting awhile. My observation was that the seal looked pretty dry. ...and it was definitely leaking FROM the seal. Is it fixed? I don't know, hope so. ...but I'm pretty sure it was the seal.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Did you torque the new nut to 180ft lbs. I think that's were I messed up. Something to do with the crush sleeve.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

No I did not. If you don't actually remove the pinion, you should leave the crush sleeve. ....-and if you do it that way, you want to mark the pinion nut before removal, and then during reassembly you put the nut back to that mark, plus a sixteenth of an inch.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

The seal doesn't go against the pinion.

It goes against the yoke.

Pinion has been the same size since 77 or thereabouts. AFAIK so has the yoke. "Torsen" doesn't really have anything to do with it; that's a carrier. Not related to the pinion seal.

If they changed the yoke, get the one that fits your yoke. "Torsen" is no help about that.

Not surprised the 8610 fits. Fits all the others I've ever done as well.

"Torque the nut" isn't the right way to do one of those. THIMK for a minute... consider your front wheel bearings. You rotate the nut CW until the play is taken up out of the bearings, then a bit more until there's a certain amount of preload on the bearings, measured by how much torque it takes to spin the hub. Nut torque won't tell you that. Pinion bearings work EXACTLY the same way, except that instead of tightening the nut until you get the desired preload on the bearings and then put in a cotter pin to hold the nut still, the resistance of the crush sleeve is supposed to hold the nut still. You torque the nut until the PINION bearing preload, WITHOUT the carrier being there, is whatever the spec is. Something in the 22 - 25 in-lbs (right about 2 FT-lbs) of torque to spin the pinion in its bearings, with USED bearings. The correct tightening IS NOT the "torque" on the nut. You tighten the nut, check how much torque it takes to spin the pinion, tighten it a bit more, check, … until it takes 24ish to spin the pinion. A NEW crush sleeve will take probably 180ish ft-lbs to start crushing, then less as it approaches the correct torque; anything from 120 to 160 is pretty normal at the conclusion of the procedure. This is why I HATE crush sleeves, and prefer a "crush sleeve eliminator"... with that, you select a shim that sets the space between the nut and the housing correctly, and then you can tighten the nut until it SCREEEEEEEEEEEEEEEEMZ for mercy. I can't say how much I tighten em to, but I'm guessing it's something in the 250 ft-lb neighborhood ON THE NUT. Maybe more. All that, while setting the pinion torque to 25ish IN-lbs. MUCH more likely to stay put than the weeeeeeeeeeeeenie crush sleeve crap.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

delete - sofa covered it.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

Torquing the pinion nut to 150 foot pounds is a good way to set the bearings when you are replacing the pinion seal. There is no reason to completely disassemble the rear end just so that you can measure the preload when you are only replacing the seal. 150 foot pounds is tight enough to hold everything in place and not so tight that the bearing preload will be increased.

If you replace the yoke or any other part in addition to the seal then marking the pinion nut is completely useless and will not work at all.

If you set the bearing preload at 22 to 25 inch pounds on USED bearings you are going to be replacing those bearings pretty soon. New pinion bearings in the 7.5 should only be set to around 17 to 19 inch pounds of preload, and used bearings should be set to 10 inch pounds or less.

Even when using a solid spacer (crush sleeve eliminator) you can still make small changes to the bearing preload by increasing the pinion nut torque. The 9 inch Ford uses a solid spacer with the Daytona pinion housing and the recommended torque on the nut is 200 foot pounds. Most kits for other rear ends recommend 125 foot pounds on the nut, but you can increase this if you need one or two more inch pounds of preload on the bearings.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

I agree, the seal goes against the yoke. I did say pinion at one point. Meant yoke.

....The "torsen" reference was more to illustrate "later year", which had the different yoke, assuming the pinion and yoke BOTH came from the same later, torsen equipped car. I suppose I assumed quite a bit. ...I suppose I should've said that I had a later model differential, and could potentially have a later year yoke...and approached the question that way.

Re: Pinion Seal - Thirdgen rear w/4th gen torsen diff
 

I was wondering about this...thanks for clarifying, and for posting this. I have a 4th gen axle that will be donating it's 3.42s, Torsen diff, T/A cover, and LS1 brakes. And now...it's yoke. I'd have never known they were different...until I went to buy a seal I suspect. :thumbsup: