Bad AW4 leak.

I've had a pretty bad leak from my trans for a couple months, gone through about 3qts of fluid in about 2 months. Anyways, when I took it to my mechanic he basically told me it was getting to hot and the fluid was just flowing past the seals.

So I put in a "high performance" tranny cooler from Advance. That fixed the overheating but not the leak, so I went back to the mechanic and he told me he would have to pull it to really find out what was going on. At almost $800 in just labor I said screw that, I'll figure out how to pull it myself, and if I messed something up while doing that I could probably find a used one for cheaper still.

Well, I'm pulling it next weekend and I wanted to get some ideas of what the leak may be, even though it's probably almost impossible to tell until the trans is out. First of all, the AW4 is out of a 98 with 125,000 miles. I'm pretty sure that it's coming from the bell housing, and it really seems to puke fluid when decelerating (billows smoke when getting off the highway). Other than those two things, I have no idea what's going on. Anyone have any ideas or gone through anything similar?

I assume your mechanic would have checked this, but is the fluid at the proper level? If it's overfilled you would experience the symptoms you're describing. What does it show on the stick when running and warm?

The leak started before I ever put in any extra fluid, the only other time the fluid was touched was at about 100,000 when the pan gasket needed replaced.

Where is it leak from? Off the top of my head sources for a leak are: Front pump to transmission o-ring, torque converter to pump body seal, pan gasket, vent tube, transmission to rear adapter, transfer case input or drive shaft seal, shift rod, cooler lines, cooler fittings, and an electrical plug or two.

Sounds like the input seal or pump body O-ring to me.

Sucks to have to drop the tranny over a 5 dollar seal, but it happens.

Make sure you disconnect the torque converter from the flexplate before dropping the tranny to avoid damaging the TC neck where it slots into the transmission, there are 4 15mm bolts that hold it on. Lube the new seal before reinstalling the torque converter and make sure the converter is fully seated before putting it back in the jeep, laying a straightedge across the bellhousing face should leave you a little space between the converter and the straightedge, even over the snout in the middle.

Talyn said:

Where is it leak from? Off the top of my head sources for a leak are: Front pump to transmission o-ring, torque converter to pump body seal, pan gasket, vent tube, transmission to rear adapter, transfer case input or drive shaft seal, shift rod, cooler lines, cooler fittings, and an electrical plug or two.

Click to expand...

I have no idea, It's definitely coming from the forward part of the transmission though. I've been told front pump seal a couple times, as well as the shift linkage seal. I figure it's just a guessing game until I pull it though.

The shift linkage seal is easy to see without doing any mechanical work, so just shoot it with brakleen to clean it off then run it for a while. If it gets covered again replace the seal.

It would probably be a good idea to give the transmission a good cleaning then a short run just until it starts to leak. Easier to find where it is leaking from then.

Talyn said:

It would probably be a good idea to give the transmission a good cleaning then a short run just until it starts to leak. Easier to find where it is leaking from then.

Click to expand...

I have a couple different times, all I've been able to tell is that it's coming from at or near the bellhousing.