For a few weeks now whenever I'm on the highway once in awhile I get a smell of gear oil. Lately, I don't even have to be on the highway for the smell to come in the cabin. It doesn't do it all the time just once in awhile. I put my cat up on ramps and got under it looking for a wet spot, and everything was mostly dry. I was hopeing to find a wet spot so I knew where my problem was coming from. I had been thinking of doing a Transfer case oil change and I have the oil to change it with, that would be the only place I could think of where I would be getting gear oil smell coming from, they wouldn't use that kind of oil in the tranny. Can anyone give me any other idea? I checked the axal ends to see if they were wet, and they were dry. I looked all under the engine compartment to see if there was any place under there with a lot of oil splash, but I found none. Anyone have any idea's where the smell might be coming from.

 

I get gear oil smell too from my 02 from the transfer case vent. Took me a very long time to figure this out, and it happens after I've been on the highway just as you said.

 

While I was under it, I didn't see any vent. Is the vent on top of the transfer case? Where is it located at, can I take it off and clean it? What did you do to stop the smell? I can't find any leaks, this maybe my only option to get the smell out. Mine is a 02 also.

 

If you have done your research with the transfer case you will probably understand the whole problem with filling it is that you can't really get to the fill valve. As I understand, just how you can't get to the fill valve, it is very hard to access the vent. The only way to get rid of the vent and have the smell go away for good is to get an 04+ transfer case that didn't have the vent because it didn't use the viscous coupling and therefore didn't produce excess heat. I have never been able to stop the smell and know others around my area who also have this problem with their 02's. The way I understand it, the smell means that your transfer case is filled which is a good thing. The reason I think that is because as soon as I replaced my transfer case fluid, the smell got very bad for about a week because it was so full. In the summer, when it gets hot out, I get the smell on and off for a little bit. If the smell really bothers you, you could try to put some shielding over the exhaust because the only reason that this actually smells is because the gear oil is being burned off via the hot exhaust fumes.

Also, if you haven't already, please replace your transfer case fluid. I can't stress this enough. It WILL save you $3000 down the road the sooner you do it.

 

I have done plenty of research on this car since I've had it. More than I did before I bought it...LOL But, I have it in the air now and I'm going to let it sit like that for the weekend and see it there are any leaks anyway. But I'm going to change the fluid, before I take it down.

 

The 04+ does have the vent, just no viscous coupling inside. If you overfill the transfer case on any year it will leak from the vent onto the exhaust and smell.

The other possibility is that the rear seal on the transfer case is leaking. This is where the rear driveshaft connects to the transfer case, and you can tell by looking at the underside of the car directly above where the driveshaft bolts to the TC flange. The oil makes it's way through the seal, through the flange, and seeps out where the driveshaft bolts on. As the driveshaft spins it flings oil 360° around, so you will see the film of oil on the underside of the car as well as smell it being burned off the exhaust.

 

Thanks for that tip, I'll look when I get the chance to get into the garage. I didn't notice any oil on the drive shaft when I looked at it, wouldn't it also go to the rear of the car and onto the drive shaft if it was coming from the seal? Thanks

 

You should also see some oil on the exhaust pipe on the passenger side next to the transfer case. That's usually the spot it falls after coming out of the vent. Which makes the smell stronger since it falls right on the hot pipe. I rather put up with the smell once in awhile knowing that the transfer case is full rather than wondering if it's empty.