Transmission Temp towing 6500#

[Buckwheat]

HI Folks,

I have a 2002 2500HD Crew Cab short Bed Sierra with Automatic Transmission 6.0 with the 3.73

I added an aftermarket temp gage ( glow-shift) and used the test port on the 4l80e for the sensor.

When towing, I have seen the temp stay around 185-200 and sometimes around 215 and once it got to 225. Tow Haul mode was used the whole time.

 

First, Im wondering was the test port was the best place to put the temp sensor?

 

Also, from a thread or so down someone mentioned using a larger auxillary cooler which Im going to use with my tiny OEM axuillay cooler....gonna order it today.

 

Lastly, I will change the transmission fluids, filter and do a complete flush, so since Im pulling a travel trailer what can I expect to temps to reach while towing ( 55mph-60mph...some hills and some flat lands here is South Carolina).

The transmission fluid is still a pinkish to light red color and does not smell burnt or anything like that.

 

Im wondering if that test port location for the transmission temp sensor was climbing because of other factors such as exhaust heat, heat soak from the transmission etc etc. and the reading was not really accurate...but 225 really got my attention.

 

The engine temp was steady at 190 the whole time

 

Thanks for any help

 

[Formulabruce]

HI, here's my take. I have used that port for a temporary temp gauge. It seems about 5 degrees hotter than the stock one ( which you should have in your gauge cluster?) Getting the grille off its a big deal, headlights are a pin pull, and its easy. A B&M super cooler can be mounted with the posts down, so you only need to modify one enclosed bracket and hook it up in same spot cover 3X the area . Its well worth it to save the 4L80E .

Trans fluid change, make SURE, Certain, POSITIVE, you RE USE the existing pan gasket. Its a must IMHO as the filer gasket kits have a flimsy paper one. You will agree once you have it out. Try to keep Trans temps under 200 to keep wear to a minimum., Good luck!

[Buckwheat]

Thanks Formulabruce,

Im pretty sure the guy who had it before me replaced the instrument cluster and the one he replaced it with probably came from something without the transmission temp gauge....( i know what the actual mileage is) Its good to know that the glow-shift gage I installed is probably pretty close to actual temp.

I went with the tru-flow max...it appears to be a pretty good size cooler and I want to get that temp way down from where it peaked for a few seconds at 225.