Transmission Cooler on the 2009 Yukon Denali

[Ed HD]

So, I'm doing some research on adding or supplementing the transmission cooling on the Yukon, considering I'm doing a lot of city driving with it, often with 7 people inside. The other night I saw 190°F on the gauge, and it was 50°F outside. Not awful, but 170°F would've been a lot nicer. Wondering if anyone knows if there's an RPO I can look for to figure out what I have now, and if anyone has any kits they know of. And/or any other info they care to impart.

Thanks!

 

[THEFERMANATOR]

190 is of no concern. Most of the time they will get up to 190-200 because that is what engine temp is. At slow speeds, the radiator's cooler is doing all the work, and the oil will get up to the temp of the coolant passing through the radiator, so a bigger cooler won't do much at slow speeds. I know I have a MONSTER of a cooler in mine, but it still gets up to 180-190 when driving in town simply because the radiator cooler is doing all the work.

 

[Ed HD]

Gotcha. I guess I'll keep an eye on it and see what it gets to as it gets hotter. I guess I'm just of the mindset that cooler is better, but I know too cold can be a detriment too.

 

[wyrmrider]

What Motor and Trans?
I'm thinking 4L60 or 4L80
If so I have a similar project
first either double change or do the drain and flush to Allison Transend TES 295
why
Better Cold weather AND Hot performance, much longer life- like forever in your application unless diesel and lots of towing or snow plowing
best brand is the Fully Synthetic CITGO QuatraSyn (not on Allison's list but is Type IV-V synthetic) but any is better than DEX III or VI
(most are type III hydrocracked dino oil synthetic- still better than DEX VI) and Dex VI may not be compatible with pre 2007 trans teflon parts- Dex III is way obsolete- change often if you use it
If you do use a DEX III type fluid get one that is certified Allison TES 389 or MOPAR ATF +4 (considered synthetic) are the only ones where you can be sure of what you are getting
if you have the little "add on cooler" in front of the radiator change to a larger PLATE (not tube and fin or stacked flat tubes) cooler look for roughly 11x11 or 12x12 with half inch fittings you can get a transdapt (or other adapter) and install an inline filter-- why? if your converter clutch lets go it will junk your radiator and your aftermarket cooler- so put the filter in the trans output line (the Allison come with one)
I recommend going to 1/2 inch lines and they do NOT have to be super high pressure hose- just oil prof
If you are on a budget a engine cooler from a FORD from pick a part is a great value- you can spot them easily