Transmission Temp Way Up

[GCinSC2]

I'm in the minority and granted this ain't helping the OP but my 6 speed manual doesn't suffer from this problem. I pull that I-77 grade from NC to VA Fancy Gap yearly too. Fifth gear and enjoy the pull.

OP good advice to watch out for excessive trans temps.

[Denis4x4]

I had the same issue with a 2012 at 950 miles. Had to be flat bedded to the dealer. I insisted that the transmission pan be dropped, filter changed and fluid replaced. During that process, the techs discovered a kinked line to the cooler and replaced it. Never trusted the truck after that and took a beating when I traded it in.

[rmatkovich]

I have been towing for forty some years. have had a trans go out with 213,000 miles on it and was happy at that millage, nothing last forever. Temp at 200-215 is not to bad but with a add on trans cooler U can keep the trans oil much cooler. The cooler the better it is. hot oil breaks down fast. Cool oil will last a long time and will not break down as soon as hot. Coolers R inexpensive and a good investment to save yr trans. As for power on Yr Denali, it has plenty of power for that trailer. Remember going up a steep hill can slow U down but going down U will go as "fast" as anyone else. Good luck

[ROBERT CROSS]

Originally Posted by rmatkovich

The cooler the better it is. hot oil breaks down fast. Cool oil will last a long time and will not break down as soon as hot. Coolers R inexpensive and a good investment to save yr trans. .....

False....it's much better to keep the temp in the recommended range .
In fact most quality coolers will have a cold weather bye-pass valve to insure quicker warm-up temps.

Bob

[jcl]

Originally Posted by ROBERT CROSS

False....it's much better to keep the temp in the recommended range .
In fact most quality coolers will have a cold weather bye-pass valve to insure quicker warm-up temps.

Bob

Agreed. My factory transmission cooler on the X5 utilized engine heat to warm the transmission fluid on cold starts, as the engine warmed up much faster than the transmission. The circuit was designed to reduce accelerated wear on cold start, and improve shifting performance.

Jeff

[SpletKay06]

Originally Posted by rmatkovich

I have been towing for forty some years. have had a trans go out with 213,000 miles on it and was happy at that millage, nothing last forever. Temp at 200-215 is not to bad but with a add on trans cooler U can keep the trans oil much cooler. The cooler the better it is. hot oil breaks down fast. Cool oil will last a long time and will not break down as soon as hot. Coolers R inexpensive and a good investment to save yr trans. As for power on Yr Denali, it has plenty of power for that trailer. Remember going up a steep hill can slow U down but going down U will go as "fast" as anyone else. Good luck

You want your transmission fluid to run 180-200 degrees and synthetic fluids dont break down tell after 240 degress for an extended time. If your temps are lower that that your wasting efficiency

[abqdor]

OK, here's where I am to date having started this thread. Lots and lots of opinions here about transmission temperature. I have also done the following:

• Emailed "socialmedia@gm.com (about tranny temp range and at what temperature the alert light goes on....no answer yet)
• Had transmission fluid checked for discoloration or odor (no issues found)
• Talked to GMC service tech who showed me that an auxilary cooler would be hard to squeeze in
• Talked to Airstream service mechanic who felt that ambient temperature and steepness of hill was definitely the contributing factor
• Spoke in person to another Airstream owner who was towing a 30 ft. Airstream with an '05 Yukon XL and felt my Denali was plenty for a 25' FB
• Talked to a reputable transmission shop who said they could find a way to put an auxilary cooler in, but said I probably wouldn't see much of an improvement over the factory set up that was already in the Denali tow package

Two simple things I've learned that I didn't do, but should have:

1). Turn off the air conditioner when temps go up. Go so far as to turn on the heater to distribute engine heat which will bring engine temperature down, which will bring radiator temperature down, which will help bring transmission temperature down.

2). High transmission temperature is acceptable for short periods of time. When it gets that hot, stop and idle the engine. Do not turn the engine off thinking you will cool things down faster. The synthetics can generally handle these high temps for short periods.

I'm sure there will be some different opinions, but I feel pretty good about the advice I've been given and am thankful for all the input.

[chaseav]

I commented having not read the OP. What I wrote still seems relevant but I'd like to add this. My TV is a 2015 Escalade with 6.2L engine. It's essentially the same vehicle as yours but I wasted a bunch of money on higher trim grade. That engine is massive and it whips around my 25FB. Up steep hills through VA and WV and I monitored the trans temp the whole time. Tons of power, no weird shifting and I swear the temp never crossed 200.

My feeling is that something is up with your transmission or something is really making it over work. Maybe the transmission in your year model was insufficient for that big of an engine? Drive it till it drops, or make the upgrade. In my humble opinion, non-factory mods installed by people who haven't done dozens of them before seldom bring positive results.

[pappy19]

Ask your tranny outfit what it would cost to install a Transgo Tugged Shift Kit. If they can't find a spot for an auxiliary cooler, at least the Transgo replaces the plastic parts and makes the tranny shift cleaner. Transgo kits have been around for over 40 years and they work really well.

[GCinSC2]

Does any aftermarket supplier offer a deeper high capacity oil pan? I don't know what trans you have but Mag Hytec is a supplier of aluminum pans for trans and differentials. Might want to review that avenue.