New leaks from the rear end. Transfer case or rear pinion seal? (1 Viewer)

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Portland, OR
Photos here: New land cruiser leaks

Yesterday, I returned from a 200 mile trip to do some archery elk hunting on the Oregon coast. When I walked out to get the mail this morning, I noticed some fresh oil leaks on the driveway from around the rear of the vehicle.

After closer inspection, it looks like oil was largely pooled around the rear diff and had even sprayed against the front facing part of the spare tire. My first thought was that the rear pinion seal failed, but there are two facts that make me second guess this diagnosis.

First, the area around the drive shaft connection where it connects to the diff looks dry, except for fresh oil on the body above the flange.

Second, there was smaller amount of oil pooled near the rear of the transfer case and plenty of fresh oil sprayed onto the body above the drive shaft.

So what do you think? Is this oil from the transfer case seal or the rear pinion seal? Any advice on how to diagnose where the leak was coming from?
 
Sounds like both are leaking. They are too far away from each other for there to be confusion. Clean up your undersides. Top off the gear oil in both. Drive it and check again for leaks. Also if you have access to a lift put it on the lift. Start it and run it gently thru gears and listen for rubbing grinding of worn bearings or gears. If your like me it's time for a rebuild of both the t/c and the rear.
 
Good advice. Thanks.

Is there anything else I should be doing when I service the rear pinion seal? Should I consider replacing the bearings as long as I'm in there?
 
Good advice. Thanks.

Is there anything else I should be doing when I service the rear pinion seal? Should I consider replacing the bearings as long as I'm in there?

Check the pinion bearings while your in there and replace (I would replace them anyways depending on mileage)

I believe when you replace the seal you need to remove the Pinion Flange, and therefore reset the backlash.
It can be done yourself, but you will need a needle type of torque wench and one that is inch pounds or less.
Crush sleeve should also be replace (that is fun to crush down) and then just to the pinion bearings.

I
 
While opening the drain plug on the rear diff, I noticed hissing air from the plug. This lead me to inspect my breather tube which was totally covered with crap on the business end! When disassembled, the tube was in fact full of gear oil.

So here's my theory:

  • The breather tube finally got plugged up with debris at some point while chasing elk around the mountains.
  • While driving toward home on the highway, pressure inside the diff and axle tubes increased steadily.
  • Eventually, the pressure built to the point where it dislodged the blockage, causing gear oil to spray out of the breather soaking the spare tire and surrounding area.
  • When I parked in my driveway, the temperature inside the diff dropped causing a vacuum to form that pulled debris back inside the tube, preventing gear oil from returning to the diff.
  • The hissing air I heard when I cracked open the plug was caused by air rushing back into the diff.

I again saw no evidence that pinion seal was compromised, but it wouldn't hurt to service it at some point just as a preventative measure. The same goes for the transfer case, which is now approaching 201k miles apparently without service.

I have a feeling that the TC rebuild requires more bananas than I have to offer. Anyone care to guess how much it would cost to pay someone to do it for me?
 

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