Hey all
I'm stumped on this one. Whenever I park after driving somewhere, all I can smell permeating from underneath my ZJ is burnt gear oil. It smells like the gear oil that is in my rear differential. It's fresh oil, no real noticeable leaks anywhere, transfer case is dry-no visible leaks, and no warning lights. I haven't crept underneath to check everything in a couple weeks tho, way too much slush from the snow melting and the rain.
Now, the pinion seal on the rear diff is shot. If I park on a downhill slope, the gear oil will drip. I ran this by some guys at an Advanced Auto Parts where I live and they suggested that, due to the seal/bearing being leaky, it's possible the oil has been running onto the u-joint, and it's slinging off the u-joint from the rotation of the drive shaft and landing on the exhaust pipe before the muffler. Any ideas or thoughts would be much appreciated. Thanks.

 

Could be an axle seal seeping and getting oil on the rotors or drums. Just a little oil will make a big stink.

 

did you change the tranfercase fluid out? Please dont tell me you put gear oil in the transfer?

 

it very well could be the front pinion seal and also check and make the vent tube isnt plugged up with anything.

 

Bustedback-Someone mentioned that as well. I'll pull off the rear wheels and have a look-see.

tiwvr1-Haven't changed the tc fluid yet. Last time I checked it,(this past fall) it was still clean and didn't smell. And no, I didn't put gear oil in the t-case. I'm not that much of a newb.

dirtmod0-This past fall I checked the vent tube and it was bone dry. Hmm, damn, maybe the vent is clogged at the actual hole in the axle tube leading into the vent tube? When I popped off the vent tube it was dry dry.

It's supposed hit 40 outside this weekend so I think I'll get underneath it and see what I can see. Thanks for the replies, I appreciate.

 

dont know if you have this figured out...but recently a buddie of mine had a kink in the front diff vent tube. After about 200 mile snowy x-press way drive, I witnessed the tube blow off and a 'cloud' of gear oil puff from under the chassis. Overheated his front diff and sheared a bunch of tiny pieces off the gears, total replacement. There is a cheap plastic fitting that attaches the hose to the backside of the diff. housing. Give it a quick look as his was kinked, or collapsed, right after the fitting.

btw. I still can't get the burnt gear oil smell out of my garage!