Towing and safe transmission temperature?

[MurdrNali]

Ok, towed boat to lake today. Boat + trailer = 4.5k #s. Temp in morning was 80, 87-89 coming home. The drive is mostly 55-60 mph rolling county roads. Highest tranny temp reaching, on the way home, was 192.

Your denali should have a small factory trans cooler mounted in front of the radiator but if i were you i would invest in a Tru Cool 40k GVW heavy duty trans cooler to replace your factory unit. You can pick em up on ebay for around $120 and there very simple to install. I put one on my last truck (was pulling a 28' pontoon boat) and went from averaging 190*-200* to never exceeding 155*-160*. Pretty cheap insurance in my opinion considering heat is what kills a transmission.

 

[Zed 71]

Pulling my 6800 lb race car trailer I'll see 210-220 trans temps if I leave it in D. So I pull it into Manual mode and leave it in 5th to reduce the trans hunting between gears. And on long grades I'll put it in 4th for the same reason. If I hold a lower gear the trans temps rarely get above 200, which is perfectly fine for a good quality oil. It's the constant shifting when leaving the drans in D with a lot of weight behind that causes all the friction which means heat.

These are the temps I see also, but we have a lot of hills around here and the ambient temps in the summer are around 100F. However, I have the 5.3L and 4L60E tranny. Looking to upgrade the tranny cooler though.

 

[jdpber]

your factory cooler is about 3X6 and well to be honest it doesnt do jack for cooling maybe a couple degrees.. Now if you plan to tow alot in the summer and your temps are higher. i would sujjest an aftermarket cooler.. this is what i did when i built my trans. i have a 15x18x0.75 cooler and it sure does a world of difference..

in town 90* outside 100-115 air intake the trans will be 135-145
90* towing my camper i am 180s with hills..

 

[SangerZ28]

I just came back from Lake Oroville this weekend. Going down I-5 south toward Sacramento I was maintaining around 174* with temps in the high 80's. When I was on 580 west and climbing the Altamont Pass, temps were 92* and my tranny never broke 195*. This was in my 2008 LT3 Tahoe with aftermarket tranny cooler that I just installed a week before. I was towing a 3500# boat, 5 people in the vehicle and all our camping/boating gear.

 

[yukon702]

I would pull over if my trans temp went over 200°
Mine never gets over 180-190 in the triple digit Louisiana summers.
On a mild day it stays about 160°

You'd be pulling over every single hour here in Las Vegas

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[swathdiver]

I tow a 6800# boat during the summer months with my '07 Denali.

You might be overloaded. What's your Gross Combined Weight (Vehicle + Boat/Trailer)?

 

[ScottyBoy]

You'd be pulling over every single hour here in Las Vegas

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Yeah, but that's in the middle of the damn desert too. You can pretty much expect temps like that in those conditions.

 

[yukon702]

Yeah, but that's in the middle of the damn desert too. You can pretty much expect temps like that in those conditions.

Yupe and that's because I'm not towing anything and i installed a bigger transmission pan which didnt do jack btw. Can't wait till it burns up or starts slipping so i can have reason to install a project 4l80

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