Leaking Pinion Seal....here's why...

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Sykoslug

Sykoslug

10 Year 15 Year
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Feb 27, 2008
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30
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Las Vegas - Nevada
Well, sometimes if it ain't broke don't break it.

I decided to grease some of the zerks on my drive shaft about 2 months ago. I noticed after pumping a fair bit into the zerk that sits just on the drive shaft behind the u joint to the tranny, that the drive shaft was actually being pushed rearward:hhmm: As if the two halves were separating from too much grease pumpage.

Now after some miles the rear pinion seal is leaking - damn. Have I damaged anything in the third member? Is my daily driver in danger of needing differential surgery? If so, anybody in Las Vegas have experience with this and want to give me a hand replacing the seal and other parts if necessary....

***I am hoping I can simply replace the seal for now and go on my way...***

BUT Eventually I would like to alter my gear ratio to - maybe go up to 4.11's or 4.56's that they want to pass on, please let me know. I might consider one big mod/repair.

:cheers:
 
I have a question related to this as well. To replace the pinion seal, one has to remove the pinion flange, and that nut also adjusts the backlash for the differential. Does this mean that one has to remove the diff to reset the backlash when replacing the pinion seal or can you set it close enough by eyeballing the depth of the pinion in the pinion nut?
 
Depends on who you talk to.

Later cruisers used a crush sleeve when setting up the diff. You tighten the nut on the pinion forcing the outer pinion bearing into the race. When you have crushed the sleeve enough, there is proper preload on the outer pinion bearing. Some maintain that there is nothing wrong with reusing a crush sleeve. I disagree. You would be dollars ahead to just replace the sleeve while you were in there.

Now, it is likely that the outer pinion bearing has managed to wear down the pinion race. This is pretty common. You cannot kill your diff by greasing a zerk. I have gotten by for short periods of time by just tightening the pinion nut forcing the bearing back into the race. But that is a temp fix.

Backlash for the Diff is adjusted by the spanner nuts on wither side of the carrier in the diff. Pinion preload is adjusted by either shims and a spacer or a crush sleeve.

With the shim style, you can change out seals all day long without issue. With a crush sleeve, it is best to replace the sleeve everytime the nut gets loosened.
 
Mace said:
Depends on who you talk to.

Later cruisers used a crush sleeve when setting up the diff. You tighten the nut on the pinion forcing the outer pinion bearing into the race. When you have crushed the sleeve enough, there is proper preload on the outer pinion bearing. Some maintain that there is nothing wrong with reusing a crush sleeve. I disagree. You would be dollars ahead to just replace the sleeve while you were in there.

Now, it is likely that the outer pinion bearing has managed to wear down the pinion race. This is pretty common. You cannot kill your diff by greasing a zerk. I have gotten by for short periods of time by just tightening the pinion nut forcing the bearing back into the race. But that is a temp fix.

Backlash for the Diff is adjusted by the spanner nuts on wither side of the carrier in the diff. Pinion preload is adjusted by either shims and a spacer or a crush sleeve.

With the shim style, you can change out seals all day long without issue. With a crush sleeve, it is best to replace the sleeve everytime the nut gets loosened.
Click to expand...

I remember the crush sleeve debate and remember someone mentioning being able to convert a crush sleeve setup to a shim setup. Is that possible?

Backlash is when the ring gear moving side to side, pinion bearing preload adjusts the pinion back and forth, gotcha. What's the procedure for setting the preload?
 
yes you can turn a crush sleeve setup into a shim setup.

One way is to crush the sleeve and then have a spacer machined that is the perfect width to replace the crush sleeve.
Another way is to use a different pinion.

Set up the ring gear for proper pattern, then either crush the sleeve till you get proper preload or add/remove shims till you get to the proper preload.


The reason crushsleeves are prpolar is they are a lot faster to set up in the factory.
 
Alright, so you cannot swap out the pinion seal without re-setting the preload. How do you set the preload? Is it like the trunion bearings where you measure the resistance by turning the pinion?
 
yep...

And, preload is different with new bearings or old bearings.
 
Mace said:
yep...

And, preload is different with new bearings or old bearings.
Click to expand...

Gotcha. I know it's in the FSM somewhere, but know offhand what the resistance range is for the pinion?
 
The last time I had anything to do with new Toyota crush sleeves, I had to remove them from the pinion gear and put them in a hydraulic press to get them to start collapsing. They are worlds harder to crush than domestic crush sleeves that I have seen, and I'm not afraid to replace pinion seals without replacing the crush sleeve, I've done it many times. You have to make sure that the nut ends up back in the very same place relative to the threads on the pinion gear when you're done. If you have a loose pinion gear, then you probably should get a new crush sleeve and start over. Unless there has been measureable wear on the larger, inner pinion bearing, the pinion depth will not change as it is set with shims.
 
lehiguy said:
The last time I had anything to do with new Toyota crush sleeves, I had to remove them from the pinion gear and put them in a hydraulic press to get them to start collapsing. They are worlds harder to crush than domestic crush sleeves that I have seen, and I'm not afraid to replace pinion seals without replacing the crush sleeve, I've done it many times. You have to make sure that the nut ends up back in the very same place relative to the threads on the pinion gear when you're done. If you have a loose pinion gear, then you probably should get a new crush sleeve and start over. Unless there has been measureable wear on the larger, inner pinion bearing, the pinion depth will not change as it is set with shims.
Click to expand...

That's what I was thinking. I have a leaking pinion seal in my new front axle, so I'll end up doing this exact procedure.

Sykoslug it's unlikely for you to have damaged anything, so go ahead and replace the pinion seal and you should be all set.
 
You do need need to set the pre-load properly either way. There is a proceedure in the FSM for changing the seal without changing the crush sleeve-It involves CAREFULLY tightening the pinion nut until the rotational drag is the same as it was before removing the nut-as measured with an inch-pound torque wrench. I think I would try that if not planning to off-road the truck.

I totally agree that that's an expedient to buy some time to fix it properly. By far the best fix is with a spacer. Then future similar fixes involve nothing more than tightening the nut afterwards. The disadvantage of a crush sleeve in hard use, is that a blow to the companion flange can artifically crush the sleeve more, and then you loose the preload on the pinion bearings. That isn't a happy place to be.

A worn out pinion bearing is common and a whole different thing. Then you just need to get the diff rebuilt. While having them do that, have them install a spacer instead of a sleeve. Our local diff guy, who I like very much, machines a spacer out of a D60 spacer on his lathe, and charges an extra $35 to set the diff up that way. The last time I was there he said="Don't tell me, you want a solid pinion spacer, right?" LOL. I've been there too many times.

Last bit of crush sleeve trivia-land Cruiser diffs were set up with a solid pinion spacer through 1978, and then went to crush sleeves with the 3.70 diffs, at least in the USA. So the ideal diffs for a fine spline 4.11 swap are the 1978s.
 
Cruiserdrew said:
Last bit of crush sleeve trivia-land Cruiser diffs were set up with a solid pinion spacer through 1978, and then went to crush sleeves with the 3.70 diffs, at least in the USA. So the ideal diffs for a fine spline 4.11 swap are the 1978s.
Click to expand...

But the diffs up to 78 also had a coarse spline pinion.

Also, with a stock setup pinion would suffer from a blow to the pinion flange as well. That isn't a matter of re-setting the preload, but a problem with the design.
 
GLTHFJ60 said:
Sykoslug it's unlikely for you to have damaged anything, so go ahead and replace the pinion seal and you should be all set.
Click to expand...

Most likely, if the DS was able to move back and forth by adding grease to the driveshaft U joints, the pinion bearing is toast.
 
Mace said:
Most likely, if the DS was able to move back and forth by adding grease to the driveshaft U joints, the pinion bearing is toast.
Click to expand...

The pinion moving farther in wouldn't cause it to leak, would it? True though, the bearing may be toast.
 
GLTHFJ60 said:
But the diffs up to 78 also had a coarse spline pinion.

Also, with a stock setup pinion would suffer from a blow to the pinion flange as well. That isn't a matter of re-setting the preload, but a problem with the design.
Click to expand...

Wrong on both counts. The 78s had fine spline pinions. Coarse splines were through the end of 77 (thoug a few early 78s may have had coarse splines. I have 2 78 sets and both are fine spline. The bolt pattern of the flange also matches through 10/84.

A blow to the companion flange is only a problem IF you have a crush sleeve, which then crushes more. That's why a solid spacer is so desirable, it makes for a stronger set up.
 
Cruiserdrew said:
Wrong on both counts. The 78s had fine spline pinions. Coarse splines were through the end of 77 (thoug a few early 78s may have had coarse splines. I have 2 78 sets and both are fine spline. The bolt pattern of the flange also matches through 10/84.

A blow to the companion flange is only a problem IF you have a crush sleeve, which then crushes more. That's why a solid spacer is so desirable, it makes for a stronger set up.
Click to expand...

Ah. 78 was the transition year, gotcha.

That's what I was saying. The problem resides with the crush sleeve in itself. I would love to convert my diffs to a solid spacer.
 
Crush sleeves should never be re-used. Period. (as always, here's an exception) IF you have to get by for a short while, you can put a few shims over top of the old crush sleeve to buy a little extra crush & time before proper maintenance is done. Generally by the time your pinion is loose, you need to re-bearing the diff.

The fine spline pinion shaft is not really that much stronger than the coarse spline ones. The main reason for breakage is not over-torquing the shaft, but from running poor u-joint angles and binding the u-joints (as is common in SOA trucks).

There was no spacer on the pinion shaft of Land Cruisers, the "spacer" is a machined step in the shaft. The mini-trucks ran spacers. Some aftermarket items may vary the approach, and as always your mileage may vary.

Over-greasing the driveshafts can and does cause wear and damage to Tcase output bearings and pinion bearings. It can also cause you to destroy your transfer case (rare). From time to time, one must remove the zerk on the drive shaft and fully compress it to remove old grease. While you're at it, mark the shaft, separate the splines and clean out all the old crusty grease. Apply a thin layer of moly grease to the spline and put it back into position according to your marks. Grease it very conservatively... you want the grease to be able to leak past the splines to keep it all lubricated.


HTH,

John
 
Wow, thanks to all for adding perspectives to what I naively thought was a simple leak. To add a few details: when my DS 'moved' it moved about a full inch- only now has it started to slide back into position as I can see grease squeezing out from the 'spline' joint- so it seems the DS movement back to original position and the pinion seal leak coincide.

What's next in order to get it back to normal?, sounds like I need to:
1-replace pinion bearing(s)
2-replace crush sleeve
3-replace pinion seal

If I am rebuilding the rear- how much more work/expense is it to swap my 3.7 gear for a larger one? And what do you recommend for a truck that lives as a daily driver and wheeler? 4.11's, 4.56's, or up to 4.88's. (I am running 33's, and have the 3B turbo'd and mated to a 5spd gearbox)

With no added weight my current ratio is fine, but add girl gear and dog and we get slow especially with Turbo Lag at low RPM's.

Lastly (and perhaps Mace can best help here) Who in Las vegas is trustworthy that might be able to do the work?

I wish I could, but I don't have tools enough from what I have read about this job. And time is almost as scarce.

-all the best,
Ryan (sykoslug)
 
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