Tranny over heating while towing

[Chris]

We did get off the original topic, but there was a lot of good info in the sub conversations and you have your cooler in and operational now

 

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[Grumpy Tooch]

We did get off the original topic, but there was a lot of good info in the sub conversations and you have your cooler in and operational now

 

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yes I agree that's what I stated in my last post I definitely appreciate all the information whether it was on or off topic

[Grumpy Tooch]

I don't get it I just did a flush this weekend all new transmission fluid I have a bigger cooler and I'm still pushing over 200 degrees in traffic yeah I'm pulling my trailer and I have a load of lumber on the truck but it still shouldn't make a difference I don't know what else to do there's always going to be traffic

[music]

Someone needs to remind me why 200F is bad for the transmission? The transmission and engine coolant both pass through the radiator, side by side, and the engine coolant is at 210F. The transmission oil is heated by the engine coolant, by design. GM's "limp mode" for transmission temp kicks in at around 265F. I hope that nobody shows that old chart from the 70's put out by an after-market radiator manufacturer showing fluid life vs temperature. It wasn't accurate then, and it sure isn't with today's fluids.

 

Electric fans are the most effective "cooler" in static stop/go traffic. If the truck already has those, then that's about all that can be done. Personally, I'd just change the fluid every 50k miles if towing a lot.

[LongrangeLauber]

I think what he's trying to get at is that he has an oversized cooler and efans and he's still seeing 200+ degrees temps. on a truck that is made to tow. I know personally I don't like seeing anything over 200.

 

And factory recommended trans. fluid change is 30k not 60k. 60k is for manual tranny, 30k for automatics. I would say do a change every 20-25k since he tows everyday

[txab]

Have you checked the temp using a scantool? Maybe your gauge is off. Wouldn't be the first time I've seen it. Also your trans may be slipping some increasing heat.

 

I'm not worrying about 210* temps short term

[LongrangeLauber]

I know when I saw 180-210 cruising down the highway that was a sign that in a couple months I needed a rebuild, cause mine went out on me haha

 

And like txab said, could be slipping, or, and I think I said it before, maybe the pump's seals are rotting away. Not moving the fluid as much or as fast as it should be

[Chris]

I saw 200 short distance with the 9300 pound toy hauler. It isnt a big deal to hit 200 while towing. 230 is where I would worry

[CKNSLS]

I read where GM says the New Dexos Tranny fluid will be good up to 275 degrees. I don't think around 200 is anything to worry about. Again, your DIC will tell you if your transmission gets too hot!

 

 

WHO HAS SEEN THE DIC (transmission hot) MESSAGE ON THIS ENTIRE THREAD? PLEASE TELL US ABOUT IT!

[Chris]

I have once a couple years ago. No cooler and clutch fan towing 9300 lbs with the old 4.8. I also had no trans temp gauge

[Grumpy Tooch]

yeah I know that the book says between 180 and 200 is OK and today when I posted this I was in traffic and it went up to 212 degrees it stayed there and didn't go any higher but also I forgot to mention that the truck also was overheating and I had to drive with the heat on to bring it down that's another thing that worries me

[txab]

Have your cooling system checked, including the radiator for blockage. Replace it with a larger capacity model, if necessary.

[CKNSLS]

yeah I know that the book says between 180 and 200 is OK and today when I posted this I was in traffic and it went up to 212 degrees it stayed there and didn't go any higher but also I forgot to mention that the truck also was overheating and I had to drive with the heat on to bring it down that's another thing that worries me

If your truck is overheating that's a diifferent issue from the transmission.

[CKNSLS]

I have once a couple years ago. No cooler and clutch fan towing 9300 lbs with the old 4.8. I also had no trans temp gauge

 

OK-thanks. So you really have no idea what the transmission temperature was. And since you didn't have a tranny cooler-you didn't have the tow pkg. Not giving you a hard time-just separating out the facts.

[CKNSLS]

Someone needs to remind me why 200F is bad for the transmission? The transmission and engine coolant both pass through the radiator, side by side, and the engine coolant is at 210F. The transmission oil is heated by the engine coolant, by design. GM's "limp mode" for transmission temp kicks in at around 265F. I hope that nobody shows that old chart from the 70's put out by an after-market radiator manufacturer showing fluid life vs temperature. It wasn't accurate then, and it sure isn't with today's fluids.

 

Electric fans are the most effective "cooler" in static stop/go traffic. If the truck already has those, then that's about all that can be done. Personally, I'd just change the fluid every 50k miles if towing a lot.

YOUR POST MAKES TOO MUCH SENSE!