Thread: pinion seal

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I noticed the pinion seal on the differential is leaking. Talked to a gear head at work and he said just take off the yoke and replace it. Said the crush is set by the nut inside the diff on the pinion shaft end, so just bust it loose, swap the seal, and tighten it back up.

When I took the yoke off ( nut wasn't very tight at all ) and started cleaning up around the seal prior to removal, I noticed the pinion was sloppy loose. Figured ah schizae the bearing is mussed up.. means gears are probably trashed too. So, today I pulled the cover off, and got a look at the gears.. ( NOT BEFORE BUSTING OFF THE HEAD OF ONE OF THE BOLTS.. @#$) and the gears look perfect. in fact, they look NEW. So it occured to me..

The pinion must have been slopping around because the yoke keeps it centered / aligned from the front. Soon as the yoke was put back on, everything was golden, right?

So, I am ok to swap the seal then right? ( soon as a drill and tap out the broke cover plate bolt, of course! )

Well – maybe. Depending on which read end you’re running. The illustration below is representative, but should be close enough for discussion sake.

The pinion shaft is pulled tight against the rear bearing (7) as the yoke (2) is pulled tight against the front bearing (4) as you tighten the nut (1).

The seal (3) is probably shot, thus the leak. You can put in a new seal and then check to see if all good and snug after you torque the yoke back into place. There should not be slop there at all (aside from the measurable backlash between the gears). If all is good, remove the broken bolt, replace gasket and rear cover, fill with oil, and you should be okay.


Good Luck,
Glenn

You should be fine.Just be sure and not over tighten the yoke/pinion nut as it and the crush sleeve set the pinion bearing preload. Lots of guys overtighten that nut and burn the pinion bearings out. P.S. red locktite on that nut,some will say use a new nut but I've done hundreds of em as described. Oh and don't forget to use some lubricant on the seal lip.

Good advice, re: over tightening. I too like red Loctite and have never replaced the nut with a new one either.

I wonder what your "gearhead at work" drives? I never saw a rear end with a nut on the inner end of the pinion!

Originally Posted by R Pope

I wonder what your "gearhead at work" drives? I never saw a rear end with a nut on the inner end of the pinion!

I may have misunderstood what he said...

Be sure and use sealer on the housing before you put the seal in, or it will seep a little.