Pulled a 6500 lb trailer yesterday for 20 miles at 65 mph. The air temp was 85 and my tranny reached about 205 and held steady. I've seen it go as high as 217 on a long steep grade while pulling same trailer. I have the 3.73 ring gears. Normal highway driving with no load, I see about 165 - 190, depending on ambient temp.

 

My 07 Suburban hits 200-210 degrees when pulling a 3500 lb trailer on flat ground. Its at ~160 degrees normal. If I hit a grade or the outside temp goes up will I wish I had an aux. cooler? if so, should I go with the factory unit so i dont have to cut into hard lines? It also might seem that I will not need a really big one?

 

ZX,
I must have overlooked your post so will answer it now. My Yukon came with a factory "Optional" cooler. It is listed on the window sticker on the right side under "Options & Pricing" and says H.D. Transmission Oil Cooler and the price is $95. My Yukon is a 4x4 and has 3.73 gears. This item was one of my requirements when purchasing the Yukon and had a hard time finding one with it already factory installed. The dealers I dealt with were going to install one if we could not find one already factory installed, but we ended up finding one in our color. And yes I have physically inspected the air cooled cooler sitting in front of the radiator.

 

Towing capacity has been a sticking point for me the last month as I just upgraded my 2000 Tahoe LS 5.3L 3:73 4x4 to the 2008 Tahoe LTZ 5.3L 3:73 4x4. Overall I love this truck, however, after I got the new truck home and was carefully looking over the manuals, and the truck, did I determine that it is only rated to tow 6500# without NHT and that it does not have an auxilary tranny cooler. The window sticker claims that the LTZ has the Heavy Duty Trailering package (which I incorrectly assumed meant tranny cooler), but this no longer means what it once did in 2000. Subsequently, I have learned that this is now called the Enhanced Heavy Duty Trailering package (NHT) or " Max trailering package" and that NHT IS available on 3:73. Talk about dirty specmanship and plays on words. Needless to say I am feeling mislead. My 2000 which has the factory cooler (and also 110K mi) has pulled my 7800# 26' aft cabin cruiser for 500 - 900 miles depending on where we go every summer with zero troubles. I have never even changed the tranny fluid. The fluid looks and smells like the day the truck was new.

Can anyone please tell me, completely, what NHT is? I hope this $95 factory option is just the tranny cooler.

I have found this GM accessory that I hope is infact this NHT cooler GMPN 19171483

http://www.gmaccessorydealer.com/det...?prod_id=97138

Can anyone confirm this?

Any other insight is greatly appreciated.

 

Has anyone installed this OEM cooler? is it easy enough, I too would have thought it would have been included with my "towing package" as my previous Tahoe had the oil and trans cooler included in the towing package.
I don't really tow but I'd like to have the extra cooling capacity for these hot Texas roads in the summer on road trips.

 

I have been reading the trans temps. I bought my tahoe a few months back. When driving around town the temp is between 175 and 195. Even if the temp is cool outside I notice it rises. This worried me because we bought a travel trailer. Driving on a flat surface going 65mph pulling out 5800 pound trailer the temp got up to 235. I want to install a trans cooler but it seems the temp runs high without towing.

 

Welcome to the forum...
Do you have the external cooler? if not do consider adding it, I did and the temps now run easily 20 degrees cooler....

 

Here is the process if interested
https://chevroletforum.com/forum/tah...install-35484/

 

Anyone familiar with RPO codes? My2004 Astro had a label on the door which listed the codes. The codes tell you precisely how the vehicle was built: rear end ratio, trans cooler, etc. I haven't found a label like this on my 2010 Suburban. Does GM still use this system? Is it located in an obscure place?

 

Welcome to the forum.

Try looking inside the glove box or console.