Trans Temp And Coolant Temp On Gmt Denali

denali texan · July 13, 2009

Hi guys,

I have been towing my 6,500 boat with Yukon XL Denali. The trans temp has been over 230 a couple of times and the coolant temp moves up between 210 and 260. Everything seems to be fine, I am just planning a 2,000 mile trip and want to make sure those temps are ok? I cannot seem to find the normal temps for the trans. Is it normal for the 6.2 to run a little warmer than normal? My old 2003 sub with 5.3 never budged while towing. Thanks,

txab · July 13, 2009

Those temps are a little too warm for me. I'd add a larger auxillary trans cooler for one. Maybe an 11" x 11" x 3/4" sized stacked plate cooler.

Ranger · July 13, 2009

^ Dumb question but I can't seem to find an answer...Are there adapters to thread the factory connectors to an aftermarket cooler or any ideas on how to make it work? I'd like to do this to my truck but don't want to be pulling my lines off and finding out it won't work.

texx · July 13, 2009

Hi guys,

I have been towing my 6,500 boat with Yukon XL Denali. The trans temp has been over 230 a couple of times and the coolant temp moves up between 210 and 260. Everything seems to be fine, I am just planning a 2,000 mile trip and want to make sure those temps are ok? I cannot seem to find the normal temps for the trans. Is it normal for the 6.2 to run a little warmer than normal? My old 2003 sub with 5.3 never budged while towing. Thanks,

http://www.derale.com/oil-cooler.html

He's a link to this subject. http://forums.corvetteforum.com/c6-tech-pe...supplied-7.html

V8nuts · July 14, 2009

X2 for the derale stuff I have it on my car but will be adding one of them to my truck.

Raymond Lowe · July 14, 2009

Hi guys,

I have been towing my 6,500 boat with Yukon XL Denali. The trans temp has been over 230 a couple of times and the coolant temp moves up between 210 and 260. Everything seems to be fine, I am just planning a 2,000 mile trip and want to make sure those temps are ok? I cannot seem to find the normal temps for the trans. Is it normal for the 6.2 to run a little warmer than normal? My old 2003 sub with 5.3 never budged while towing. Thanks,

Seems pretty high on the tranny. I only tickled 200 once towing up a long hill in the summer. Then again, we don't get the Texas heat where I drive. Normal trans temps are under 160 without towing. Up to 200 when towing, maybe peaking a tad higher cresting a hill. And I've never seen my engine coolant temp above 215.

If it were me, I'd run 92+ octane, keep the speed under 55, shut the A/C off when pulling a grade, use tow-haul mode, and try not to work the engine as hard on hills. Keep an eye on that Dexron IV for darkening or funky smells and think about servicing the transmission more often.

smattei14 · July 14, 2009

Hi guys,

I have been towing my 6,500 boat with Yukon XL Denali. The trans temp has been over 230 a couple of times and the coolant temp moves up between 210 and 260. Everything seems to be fine, I am just planning a 2,000 mile trip and want to make sure those temps are ok? I cannot seem to find the normal temps for the trans. Is it normal for the 6.2 to run a little warmer than normal? My old 2003 sub with 5.3 never budged while towing. Thanks,

This worked for me...I kinda had the same problem as you.

http://www.gm-trucks.com/forums/index.php?...p;hl=trans+temp

I added a 9 x 11 stack plate cooler and when to all AMSOIL...and the max trans temp is 200 now.

PM me if you have any qu's about what I did.

I hope this helps

denali texan · July 14, 2009

Thanks for all the responses. Now I have 2 more questions.

I noticed my radiator reservoir was a little low. When cold, I was able to add a little more than a half gallon to the resevoir.

1.Is this normal loss for a 2007 with 40K?

2. Is this 1/2 gallon going to make a huge difference in keeping motor cooler in extreme temps?

Keep in mind the temp never goes below or above when not towing.

It crept up when it was 100 outside and towing over rolling hills, no mountain towing at sea level in Texas.

Thanks,

Webb

smattei14 · July 14, 2009

Thanks for all the responses. Now I have 2 more questions.

I noticed my radiator reservoir was a little low. When cold, I was able to add a little more than a half gallon to the resevoir.

1.Is this normal loss for a 2007 with 40K?

2. Is this 1/2 gallon going to make a huge difference in keeping motor cooler in extreme temps?

Keep in mind the temp never goes below or above when not towing.

It crept up when it was 100 outside and towing over rolling hills, no mountain towing at sea level in Texas.

Thanks,

Webb

Not sure about question #1...that is a tough call...you are going to lose some fluid...just keep an eye on it.

As for #2...no...1/2 should not make that much of a diff...

I would just upgrade the trans cooler to atleast a 11 by 11 stack plate. Then I would move to all AMSOIL (or some form of syn. fluids)...from your oil to your trans case to the rear gear oil...with those temps towing (you have the AWD right?)...that is going to gen. some serious heat. The syn. fluid should give you better protection, and should keep the temps down a bit more.

smattei14 · July 14, 2009

Sorry one more...remember...your old 5.3 didn't have E-Fans like your Denali (the reason why your temp was alot lower was because there was a strong flow of air at all times, cluch fan)...the Denali has E-Fans that only turn on when the coolant temp (not the trans temp) at 205-210. this is a major reason why your trans temp is so high (along with the size of the trans cooler, a stack plate is better vs the OEM Fin).

If you make some of these mods and you are not happy with the temp, you can look into a Blackbear tune (or a programmer, you can buy them on-line)....with this tune, you are able to program the fans to come on at a lower temp and stay on longer so you can reduce your coolant and tranny temps.

The e-fans were design to give the denali better MPG's (running hotter)...but they are not the best for cooling down your truck in hot weather....