pinion shaft play

[Devils Paw 80]

My 76 FJ40 rear end was leaking diff fluid through the pinion seal pretty bad awhile back, so I had it replaced. A couple months later, it's leaking a little bit again. Does this indicate that I've got excessively worn bearings in the pinion output shaft? The friend who did the job for me said he noticed some play in the shaft. Any cheap fix for this? The rearend sounds fine (at least to my ear) otherwise.

Thanks, Bret

 

[ridgerunner]

The rear pinnion leaking like that usually is a sign of a worn bearing alright.

 

[Pin_Head]

What kind of play?

Anything other than rotational play is not good. A leak could also be a sign of a worn flange sealing surface.

 

[Devils Paw 80]

Thanks guys. Pretty sure the play is rotational, which seems like it could chew up the seal.

 

[Rice]

Thanks guys. Pretty sure the play is rotational, which seems like it could chew up the seal.

Huh?

 

[Degnol]

Is this a case for a Speedi Sleeve?

 

[PabloCruise]

Can I replace my pinion seal with just a seal puller?

My vehicle is a '78 40 rear diff is leaking here - is this a crush sleeve or shim?

If it is a shim, I can just R & R and then re-torque with a new nut, correct?

 

[Devils Paw 80]

To access the seal, remove the companion flange from the pinion shaft using a puller. pinion oil seal should pry off with hand tools. If you do a search, there's more info on this forum regarding the details of replacing the seal.

 

[Pin_Head]

If it is a shim, I can just R & R and then re-torque with a new nut, correct?

Yes, shims and that is the usual drill. The only exception is if the shims have "spun" because of a bad bearing or a loose nut. If the shims have worn, just tightening the nut may give too much preload. Because of this it is not a bad idea to get a feel for how much total preload it has before you take it apart. Jack up a wheel and see how much torque it takes to turn it. You can just do it by feel if you don't have an inch pound wrench. If it is a lot harder to turn after you re-torque it, you will know something is wrong.

 

[PabloCruise]

O-k Pin Head, something is wrong. I didn't check how hard it was to turn before, but now that I have the seal replaces, I just whammo'd the pinion nut on there and now I have what feels like a lot of preload to turn the pinion.

WTF do I do?

 

[Pin_Head]

Reset the pinion preload. Iti s is best done with the axles out, but you could probably get away with backing off the nut until there is no pinion preload and measure the torque. Then adjust the pinion shim pack until you gain no more than 6-8 inch pounds when it is torqued to 150 ft lbs. I would get an adjusting washer that is .005 thicker than the ones in there now and start sanding it down until you get the right preload.

The preload changes from too loose to too tight over a thickness range of .001-.002, so check it often.

 

[PabloCruise]

Thanks man - I feel like a dumb ass - got a little exuberant in my quest to replace leaky seals...

 

[PabloCruise]

I keep going over this scenario in my mind - after I disco'd the driveshaft but before I pulled the flange I had a few degrees of rotational play, but no side-to-side slop. When I pulled the DS flange, it had a bunch of schmutz behind the shield, a thick combo of gear oil and dirt. Then when I dug in to look at the bearing, the shim did look like it could have spun.

Now, I have no rotational play.

Does that mean I was no longer at the correct pre-load? Or did the schmutz behind the shield make up for a shrinking shim?

I need yet another new seal, don't I?

 

[Pin_Head]

Unless the pinion nut came loose or the bearing was bad, you shouldn't have any problem witht he shim stack. You should be able to just remove and re-torque the flange. If you removed the shims, are you sure that you didn't loose one of them?

If you need to reset the preload, the seal has to come out.

 

[zetasig]

Sorry for coming into this late, I replaced my rear pinion seal on the 77 rear axle I just got. However I did not see/find any shim? I got the pinion seal from the dealer, and removed the old one it was very stuck in there and I ended up destroying most of it in the removal process. I installed the new one but have not run it at all to see if it is leaking.

Edit, I found the info in my FSM for a 1970, I would imagine the 1977 axle to be the same?? Looks like 144-170 foot pounds on the pinion nut.

as from Pin Head, I did not remove any shims, (since I didnt know about them) So I would imagine I just need to loosen the pinion nut and torque to proper spec. I have some rotational play right now.

Thanks Warren.

 

[Pin_Head]

You won't see the shims unless you remove the outer pinion bearing. 9 times out of 10, you won't have any problem just taking off the flange, replacing the seal and torquing the flange back on. The only time you run into a problem is when the shims have spun and got worn down a bit so they no longer maintain the preload.

 

[Pin_Head]

I
Now, I have no rotational play.

Does that mean I was no longer at the correct pre-load? Or did the schmutz behind the shield make up for a shrinking shim?

?

I need to read a little more carefully.

Rotational play is not the issue. If could have 5-60 degrees of slop and still be OK.

The issue is how much force it takes to turn the pinion. If it takes a lot more force to turn the pinion (like 3 ft lbs) after you replaced the flange than before, then there may be something wrong with the preload.

If the preload is too tight, the bearing will burn up.

 

[PabloCruise]

Alright, on a related note, can I just torque my stke nut for the t-case rear output to spec and get away with that?

I did not take the speedo housing off, so I could not have lost any shims there.

I am just a little afraid to run it all the way to torque spec and find I am fuqued on the t-case as well...

 

[PabloCruise]

I need to read a little more carefully.

Rotational play is not the issue. If could have 5-60 degrees of slop and still be OK.

The issue is how much force it takes to turn the pinion. If it takes a lot more force to turn the pinion (like 3 ft lbs) after you replaced the flange than before, then there may be something wrong with the preload.

If the preload is too tight, the bearing will burn up.

I need to describe what is going more carefully:

Before I tore the rear pinion down, I had several degrees of rotational play.

Then I took of DS flange, cleaned all the schmutz off, pulled old seal, slinger, and bearing. Bearing looked fine, shim looked a little fuqued.

I put everything back in, new seal, and just whammo'd the pinion nut with my impact wrench.

Now I have no rotational play.

It also feelsl like I need a lot of torque to turn rear pinion.

Should I just order the Rear Diff Shimset and try the next thickest one up from my spun shim?

TIA

 

[rgentry]

Sounds like you made a mistake in using an impact wrench here. You
need to use a torque wrench and measure the torque. As for whether
you need a thicker shim, you won't know until you install it correctly.
Did you run it for long like this? You probably have a monster preload
on your pinion bearings, which can't be good.