Engine/Transmission (1998.5 - 2002) Transmission Overheats :(

[ALepley]

Had my transmission rebuilt back in May this year. Everything was fine and dandy till the other week. Out of the blue it got hotttt! Normal temp was around 160 to 180 depending on highway or city driving. Now it seems to keep climbinng in temperature. It almost seems like it has no cooling ability. If I hop on the freeway and drive it will stay cool but as soon as I sit in traffic or let it idle it heats up. Anyone ever run into this? I got a BD trans pan coming for it and currently looking into a bigger trans cooler.

 

[WalterJ]

Alepley;

No trans pan is going to help when sitting still. I experienced 250+ deg climbing 3, 2,200ft peaks in western PA last month. I was down to 30mph at times. Based upon advice from local diesel pullers & racers, I now have a Derale #15960 kit on order. I plan to install it under my bed for protection from debris & salt spray during WI winters. A 180 deg thermostat is included.

 

[AClayton]

Had my transmission rebuilt back in May this year. Everything was fine and dandy till the other week. Out of the blue it got hotttt! Normal temp was around 160 to 180 depending on highway or city driving. Now it seems to keep climbinng in temperature. It almost seems like it has no cooling ability. If I hop on the freeway and drive it will stay cool but as soon as I sit in traffic or let it idle it heats up. Anyone ever run into this? I got a BD trans pan coming for it and currently looking into a bigger trans cooler.

You stated your normal temps but how high does it get when you idle? If my a/c is on and I let my truck idle for any length of time, my trans temp shoots to 200*. It will drop after driving and the convertor locks. Mine usually stays at the 150 to 160 mark as long as the convertor is locked and regardless of whether I am towing or not. Mine rarely goes to 200* and has never gone over that... . even towing my 16K lb 5th wheel. My sensor is in my trans pan.





Alan

 

[WalterJ]

AClayton:

I believe the trans pan is not the place to record the peak temps. That would be in the trans cooler inlet line.

 

[AClayton]

AClayton:

I believe the trans pan is not the place to record the peak temps. That would be in the trans cooler inlet line.

I'll meet you half way on that! Regardless, I think it gives me a baseline as to what is normal and if temps get out of control, I know about it. I know that if it gets to 240*,whether measured at pan or otherwise, I need to back off until temps cool. That is what gauges are for... . to alert us with any unusual temps or pressures. My ATS pan came standard with a 1/8th inch port for a sensor so that is where I installed it. May be why I see lower temps overall... . IDK! But for the record..... I do agree with you.



Alan

 

[CUMMINZ]

I have never seen my transmission temps higher than 170. When I stop and shoot the little red light at the xdeep pan I get about 150 and on body of transmission I get higher.

 

[Bob Cochran]

I don't have an Auto but was wondering how your water temps are running? A clogged radiator; so your not cooling the transmission fluid. Just a thought might not have anything to do with anything.

 

[ALepley]

I don't have an Auto but was wondering how your water temps are running? A clogged radiator; so your not cooling the transmission fluid. Just a thought might not have anything to do with anything.

My radiator is fine. The transmission coolers on the autos are seperate from the radiator. There is one up front by the a/c condensor. The other one is on the engine block water to oil cooler.

 

[ALepley]

You stated your normal temps but how high does it get when you idle? If my a/c is on and I let my truck idle for any length of time, my trans temp shoots to 200*. It will drop after driving and the convertor locks. Mine usually stays at the 150 to 160 mark as long as the convertor is locked and regardless of whether I am towing or not. Mine rarely goes to 200* and has never gone over that... . even towing my 16K lb 5th wheel. My sensor is in my trans pan.





Alan

Mine used to be like that until it was rebuilt. If I was sitting in traffic it would climb no higher than 180 even on a hot day. But now in hot weather it just keeps slowly climbing. It doesnt cool down until I get on the freeway at a constant speed of 65 or higher. It has gotten as hot as 240 and then it goes in limp mode. It doesnt got hot fast but it will steadily heat up. Im determined its the cooler up front so I ordered one. I will report back.

 

[Dieseldemon]

You need to monitor the supply and that is in the pan not the peak temps.

 

[cerberusiam]

Had my transmission rebuilt back in May this year. Everything was fine and dandy till the other week. Out of the blue it got hotttt! Normal temp was around 160 to 180 depending on highway or city driving. Now it seems to keep climbinng in temperature.

Thats pretty normal and its not unusual to see 220 in stop-n-go traffic in the summer. As long as your using a trans fluid rated take the temp like ATF+4 it should be Ok. ATF+4 operating tempis 140-20 degrees, as long as it stays in that range its usually good.



Its cooling down whne you get out on the hiway because you now have air flow over the cooler and when the TC is locked up its routing more fluid to the cooler plus not running in fluid coupling creating heat. With a better TC they will heat up faster expescially in slow going.



You might want to check the drain back valve for plugging if you did not remove it. They can catch a lot of garbage and restrict the flow in TC unlocked operations. Also check for debris beteen the IC and trans cooler, AC and IC, and just crap in all of them. Make sure your fan is working correctly also. Its the only thing pulling air at an idel or slow speeds and if the clutch goes it effects everything.

You need to monitor the supply and that is in the pan not the peak temps.

I think most of us agree driving by peak temps to be proactive is much better than be reactive when the pan temps get to high. Monitoring the cooler output line temps gives the operator a chance to adjust driving to minimize the problems before they become one. If all you are watching is pan temp you have ZERO idea what is causing it or how to fix it other than just stop.

 

[SnoKing]

I have a sender in the pan and one in the output line. The transmission would most likely be toast before the pan temp reacts much. With a 89 percent TC and DTT transmission other than stop and go in heavy traffic is normally runs cool.



Chris

 

[THoltz]

I agree that pan/bulk temperature is more indicative of transmission fluid heat removal problems. It seems to me that if you have an overheating problem and the truck is moving at a speed to provide adequate air flow over the cooler, then your options while out on the road are limited to stop the truck, drive in a cooler part of the day, or take a less demanding route.