AW4 Oil Leak

I have a 1998 XJ Classic 4.0 with the auto AW4.

Bought it about 6 months ago, home made 4" lift, and MT 31´s


when wheeling in sand dunes, my engine temp stays right in 210°, but I can smell burning atf oil and I leave a trail of white smoke.

went under, and found atf leaking from the tranny bell house where it gets to the rear part of the engine, the oil falls exactly on top of the exaust causing the smoke, all the tranny pan also gets all wet of atf.

Read a lot of similar problems here at , but didnt find an acurate answer.

Some say that atf starts to boil, and starts to leak from the tranny vent tube, located inside the bell housing. Solution atf radiator.

other said hot atf leaks from the atf oil pump oring, they say the pump is steel metal, and the tranny is aluminum, so there are different thermal expansion from diferent materials etc etc, causing the leak, solution new atf radiator.

Faulty oil pump oring?

So what do you recomend? just went to a pick and pull and just got a ZJ trans oil radiator, will install it tomorrow.

I also checked on the inspection plate on the tranny housing but didnt see any oil falling from it. (engine and tranny were cold)



Recomendations??


thanks in advance.

The vent tube is not located inside the bellhousing, first of all. Whoever told you that didn't know what they were talking about.

Are you sure it's ATF? ATF will usually actually burst into flame when it lands on the exhaust, you would know it if that was happening. It sounds to me like a classic rear main seal leak.

Replacing the oil seal on the AW4 pump is not bad, but you do have to drop the transmission to get at the stupid thing. It's actually a pressed in seal and costs a couple of dollars at the parts store. The differing rates of expansion should not affect anything though, since it is a rubber seal with a spring tensioned lip.

I would keep an eye on the transmission fluid and engine oil levels, whichever one goes down regularly is probably the leaking one.

engine oil level is ok, transmission oil is the one that is low, have to add a quart after going wheeling.

I think I have been lucky of not getting flames when the oil reaches the exhaust, but I am really sure it is atf.

I will replace the rear main seal, and will add the zj atf tranny cooler, new tranny filter and mexIII atf, if problem continues i will have to drop the tranny and check for pump o rings

thanks!

If the engine oil is fine, I would leave the rear main seal alone. It is quite possible to nick the new one while installing it and find yourself worse off!

Sounds like your oil pump seal is leaking as you said... especially since you have to add a quart after wheeling. I'd drop the tranny and replace the seal. Adding the cooler can only help, and it is a good time to install it while you are doing other stuff anyways.