Honestly, if the truck is staying stock, the factory cooler is plenty adequate. The trans running 180-200* is NOT going to hurt it one bit. Dex VI is much more tolerant of heat than Dex III was/is. If you install the TVS, re-evaluate the cooler install then.

 

Thanks for all the responses, that helps my decision making. I already own the cooler, it's the last part I have left to sell after trading my old truck. Since my modding is limited until the truck is paid off, I'll keep the cooler to be used at a later date.

You don't think 100* is a little on the cool side for transmission operating temperature? I would think that sluggish fluid is also a negative for proper transmission operation.

 

Transmission fluid viscosity isn't affected like engine oil. Only in rare cases where there are below freezing temperatures will the transmission fluid become thick enough to hamper performance.

The stock cooler isn't to warm up the transmission, the stock cooler is to keep it under 212*F where the fluid begins to lose its lubricative properties. If the design was to warm it up to a certain temp, GM would never offer an external cooler with its towing packages.

My transmission will start burning the clutch packs with an OE cooler holding it at 200*F. Pull it down to 140*F with a Tru-Cool and the slipping goes away.

 

If you're burning clutch packs with 300rwhp, on a built transmission, at 200*, there is something wrong with your build or tune.

 

So I got my grille off, painted the cooler black and bought the GM transmission line fittings but I'm not sure how to hook it up. I was expecting it to be like the gmt800s where I could use a compression fitting, but I don't think that will work. Anybody have a pic of the 40k on a nnbs? Did you just cut the lines and use the provided hose and clamps? I was hoping to use some of the factory piping.

 

It's very similar to the installation on a GMT800. You can cut the right line and use a 3/8" compression fitting to "swivel" the right line.

PM ak2007r6 for pics.

 

Gotcha, thanks. I think you meant the left line but I understood. I have it apart now and it's going good. I didn't realize the flex lines allowed so much play, shouldn't have any problems wrapping it up. I had to take a break and watch the baby girl.

 

Yea left line when looking at it from front of truck. Cut, put fitting on to swivel 180 and you will be good to go

 

I'm rocking one on the Denali and no regrets!

 

I got it installed. Since you guys are running such low temps, do you check your fluid on the Cold line or the Hot line? I checked my fluid, driving it was ~120 but as it set there it got up to ~140. I put some fluid back in it after the swap but it was only at the D of COLD when at 120*. The manual says it's not considered HOT until 160 (160-200). Cold is (60-90).

Used an aluminum angle on the bottom right and the supplied tie on the top left. Not centered and not perfectly level (real close) but I think it will work! No leaks!



Also, I had to relocate my ambient air sensor because it was reading at 80* while it was only 55 outside. It's better now.