ZINGGG

96 XJ with 4.0L and AW4 on 33s.

Driving up a long, steep incline today. Without fail, smoke in the rearview because of tranny fluid spilling on the downpipe. This happened after about 15 minutes of driving up the incline.

Already have a new radiator with fresh 50/50 coolant (only a few months old). Tranny cooler lines aren't pinched or rusty and in good shape. Transmission fluid is a nice fresh red color (sitting at the proper level). Also added a B&M Supercooler in line with the radiator in front of the radiator and A/C condenser. Both fans are working properly

I will also be putting in 4.56 gears sometime this week. I'm hoping that'll get my tires moving easier and help. Any other things I can do to get the tranny running cool? I havent put in a tranny temp gauge yet and plan on doing so in the near future so i can see exactly where the temp is at.

Lead Foot

Stock gears on 33s? That will over heat your tranny on long inclines like that no problem. Gears are of course recommended.

How is your trans cooler plumbed? Trans to cooler to radiator and back to trans? Are you taking these inclines with the trans manually in 3rd (assuming you're on the highway)? That will also help.

ZINGGG

Yeah I threw it manually in 3rd and it still pissed fluid. I have it routed tranny to radiator to aux cooler then back to the trans. This is the recommended way as far as I know.

I had a feeling the main cause was because I'm currently on stock gears. That'll be changing very soon. The 4.56s are just sitting in my room winking at me at the moment.

Lead Foot

Good. Get those gears installed.

ZINGGG

Thanks man

RenegadeT

I don't like heating up my tranny oil by passing it thru the engine radiator, so I bypassed it. I put an aux air-oil tranny cooler in front of the radiator on the electric engine fan side, then put a switch where I can turn the fan on anytime.

Lead Foot

Transmission fluid is generally warmer then 190 degrees coming out of the tranny. The radiator cools it.

TheCK4x4

Slap this puppy on there and you'll be good.

ZINGGG

Is that all it'll take? Shoot, I've been wasting my time and money going other routes to fix it.

I've heard about people completely bypassing the radiator or doing it the way I did. The consensus was doing it the way I did, running it in line with the factory tranny cooler in the radiator. Something about running it through the radiator because without doing that, it'll feed the tranny too cold of fluid on cold days. I don't really remember exactly haha.

outlawcherokee

Bypass the radiator, let your aftermarket cooler do the work it was designed to do. You and your trans will be happier and cooler.

5-90

External cooler with a thermostatic valve, and cut the OEM in-tank cooler out of the system.

Bear in mind that the OEM "cooler" is also a heater - it's designed to try to get transmission fluid up to operating temperature quickly, then try to cool it off. It's a balance that doesn't always work.

Shunting the fluid directly to an external cooler will cool the fluid more efficiently, and remove the thermal load from your radiator (allowing it to do its job better.)

The thermostatic valve shunts fluid back into the sump if it's cooler than the valve's threshhold (to warm it up,) or passes it to the cooler if it's over (to cool it off.) User intervention isn't required, it gets up to op temp more quickly than OEM, and keep it there because it will automatically switch back-and-forth.

B&M used to make the good thermostatic kit, but I think it's caught on all over by now.

ZINGGG

Thanks for the post, Jon. I'll see how she does once I get my gears installed. If the tranny is still running too hot for my liking, I may have to delete the OEM cooler and then see how it does. I appreciate the input.

sthon

I'm in the same boat. 32" MTR kevlars (these bastards are heavy) with stock gears. I'm working on swapping in 4.56 geared axles and long arms, hoping it will solve my problem.

ZINGGG

I'm sure it will. At least I'm hoping it will because that's what I'm banking on to solve my problem haha

sthon

No doubt, new axles and long arm longs broke the bank so it damn well better fix it.