2007 Yukon Xl

[l-man]

Hi everyone, I just got a 2007 Yukon xl with 52k mi. I was wondering if I should add a transmission oil cooler to "help extend the life" of the transmission, or should I leave well enough alone. Also, what is the deal with the throttle body spacers, are they worth the money? Kinda seems to easy to do any good.

[maxwedge]

If you live in a hot area of the country or pull a trailer the cooler is a good idea. The spacer is not going to do anything for a daily driver.

[jdmccright]

I would also add a tranny cooler if you use it to tow trailers or do frequent trips up into the mountains, or both. Even for long, highway trips, dropping the temp at least 10° below what comes out of the radiator will help alot. For a tranny, cooler is better...except maybe Alaska.

I concur with the TB spacer...pretty useless on a stock engine.

[l-man]

Thanks for the advice, I wasn't sure if you could get a transmission "to cool", I am moving to Florida soon, so I think I am going to get one, I saw a plate/fin design from Hayden that looked decent http://www.summitracing.com/parts/HDA-679/ Is this something a do-it-yourselfer can do at home with common tools? About the most diffucult thing I have done is replace a rear break rotor on a 2001 Foed Explorer. (which was pretty easy)

[l-man]

Was also going to ask about engine oil coolers???

[jdmccright]

Typical tranny fluid temps run from 190-230°. The tranny is designed to work with hot fluid, so cooling too much may make it feel sluggish. However, the fluid starts to break down and oxidize around 195°, limiting it's lifespan to the typical 30k-50k change intervals. I don't have the reference, but it is said that tranny fluids have a life span of 100k miles if kept at 175°, and every 20° increase cuts that lifespan in half. So, ideally a drop of at least 20-40° would be very advantageous. A good temp range to shoot for is 140-180°.

In a stock system, the transmission fluid lines run through a heat exchanger inside the radiator to help warm it up when it is cold and keep it from getting too hot...the coolant is kept at around 195-200° with the stock thermostat. So, cooling is limited to the radiator temp.

If your truck has a "heavy duty trailering" option package, you might have an external transmission fluid cooler already mounted behind the grille in front of the A/C condenser and radiator...approximately the size of the unit you're looking at buying. If the RPO sticker in your glovebox has the code "KNP" you already have an auxiliary tranny cooler. If so, you can stilll add a second cooler, which is easier to do, or add a thermostatically controlled auxiliary fan mounted directly to your aux cooler. The fan is a little more expensive option, but the advantage is that cooling is more direct and not as dependent on vehicle speed. Here's a small one that would fit the factory installed aux cooler:

http://www.summitracing.com/parts/DER-16507/?rtype=10

If you're not up to cutting and splicing wires, the second cooler will probably be easier. Finally, a trans fluid temp gauge is also a good idea if you want to keep an eye on it while trailering.

[EDIT] I've also read that even with the factory tow package option, temps can still creep pretty high when trailering. A second aux cooler is the cheapest and easiest route to help keep temps down.

Probably too much info, but I hope this helps you decide...goood luck!

[l-man]

That was great information, in my opinion there is no such thing as to much information. I am going to have to look and see about the factory cooler, I havn't had the chance yet. Thanks for the great advice.