mitchellsk

Hey, new member here but experienced jeep owner (wranglers, cherokees, grand cherokee, grand wagoneers).

I have a factory stock 1998 XJ 4x4, 4.0, automatic transmission.

The transmission overheats severly when in traffic. At 5 minutes I get worried and at 10+ minutes it will kill the engine.

I've already drained & refilled the transmissiona and also replaced the filter.

It is NOT NOT NOT anything to do with the engine cooling system... I've already eliminated the cooling system... it is definately the transmission or the torque converter.

It drives fine all day long... unless I get stuck in traffic.

Is it a solenoid problem?
Is it a torque converter problem?

If I have to replace the transmission is there an easy upgrade I can do?

I'm in California (and new to California) so whatever I do has to get through smog tests.

Thanks!
Mitch
Santa Rosa, CA

djb383

Have u aimed a point-n-shoot infrared temp gun at the fluid exit port/line on the passenger side of the tranny to verify fluid temp?

Roler

Welcome to the forum!

What have you eliminated , when saying eliminated the cooling system?
And is your ATF now nice and red, or did you do 1 drain/refill?
You will likely need to repeat that several times before the ATF is ok, because draining only changes out part of it at a time.

Increased temp from the trans will add to the overall temp, but an up-to-scratch cooling system should not have to tumble over with that...

mitchellsk

I haven't used a temp gun, i don't have one but the transmission gets MUCH hotter than the engine.

I've replaced the thermostat, radiator, hoses, spring in the lower hose, fluid, etc.... and done a tune-up. It's not the engine, the engine never overheats.

It's the transmission and/or the torque converter. I just don't know if a bad torque converter could cause it, bad solenoids could cause it, or if it could be something else inside the transmission.

I only drained & replace the fluid, I did not flush it. I did put a new filter in but the old filter looked fine.

The fluid is red and not dark or burnt.

Thanks

XJwonders

So how do u know the trans is overheating, what did u use to diagnose that?

djb383

^^^^^X2.....how do u know?

mitchellsk

Because the engine is not overheating and the guages are fine and when it happens the hood is too hot to open with bare hands.

Because I'm present with the vehicle and and it's obvious when it happens because you can feel where the extreme heat is coming from.

Because I've had lots of different types of vehicles for more than 35 years and know what normal operating temps radiating should feel like and these are way abnormal... not a little... it's obviously extremely hot.

When it happens it won't restart for 45 minutes until the whole thing is cooled down enough. It is related to heat from the transmission or torque converter... probably distorting the flywheel enough to increase the distance to the CPS just enough to lose the magnetic pulse that enables the engine to run... until it cools down and gets back into shape again.

It is extreme heat from the transmission or torque converter... I would just like to know if a solenoid could cause that... or maybe a bad torque converter... or something inside the transmission... or if I need to replace the transmission is there a transmission upgrade I can do easily.

Or tell me what the bellhousing temp should be and if I can find a temp gun I'll shoot it but I don't want to buy one just for that.

Thanks

XJwonders

Ideal AW4 temps should be from 150-190 degrees

Have u thought about installing an aux cooler?

djb383

This time of year, not towing, tranny fluid temp will likely be +/-150. U need to shoot the temp gun at the tranny fluid exit port (the forward port) on the side of the tranny.......not at the bell housing.

mitchellsk

I do have an aux cooler but haven't put it on yet. I shouldn't need one though... this is just happing sitting in traffic for 10+ minutes. It does help to take it out of drive but it will eventually still do it though in 20 minutes or so.

I'll try to find a temp gun but it's gotta be over 300d... it gets so hot you can't put a bare hand on the hood. The only other thing I can think of is the catalytic converter is heating up the transmission but the exhaust seems fine... no loss of power unless it's getting close to overheating.

I did find an inline temp guage that might be nice to have on all the time so I may order that soon.

Thanks for the input.

Crazy 8s

I may be sounding like Capt Obvious, but the transmission isn't positioned in such a way that its heat would make the hood hot to the touch. If the hood is hot that is because the engine is right underneath it.

If the ATF is red and not brown or burned appearing then the transmission is probably not overheating.

Perhaps you have an exhaust leak or maybe the heat shield is broken or missing? Maybe the exhaust has some blockage?

Even if the transmission is not overheating, it will be a good thing to get that cooler installed. It won't be too hard and it will make you feel manly while wrenching on the Jeep.

djb383

An auxiliary tranny cooler in the box is still the same thing as no auxiliary tranny cooler, no? One of these point-n-shoots is as handy as a pocket on a shirt. Should be standard equipment in every XJ tool box. It can be pointed at lots more than just the tranny.

http://www.harborfreight.com/catalog...rared+temp+gun

Radi

+1
AW4 will puke it's fluid out the vent long before it gets hot enough to distort the flexplate, the fluid left inside would look and smell ruined and you'd have obvious shifting/slipping problems.
All you need is a cheap IR thermometer to find the source of the heat, Here's one with a laser pointer for $35:
http://www.harborfreight.com/non-con...9465-8905.html

I see you did not replace the fan clutch or water pump. Those along with the fan shroud and electric fan are all possible culprits when you have overheating at idle, but not while moving.
What's your dash temp gauge reading?

Roler

Mine had a lot of heat coming from underneath. Improved after the cat converter was replaced. Hood temp has nothing to do with trans temp.
Going through the info, the only thing, apparently, is the heat sensation which appears to be abnormal?
No brown/burned fluid, no malfunction of the trans, no overheating. I dont know, but verify this first, I'd say. Before and after installing the aux cooler (which, I agree, has to come out of the box).

To answer some of the questions: AFAIK, solenoids are involved in shifting characteristics and ATF running hot is not related, unless its shifting is completely wack.
And an update trans is not needed, the AW4 is a very strong trans with a good rep.

XJwonders

I agree. Fan clutch and water pump is in order, and if the belt is more than 5 years old, it need to be replaced