Transmission getting Hot

[mikez71]

Yes the 07-14 runs transmission line to radiator, then to the aux cooler if equipped.

I have a 2012, 209k miles, no aux cooler yet, and it seems to get right up around 200degF as well.
Doesn't take 1.5 hrs to get there either!.. New radiator, fresh fluid.
I might try reducing or zeroing the slip in tune. I've already removed TCC lock in gears 1-3.

@NickTransmissions any general estimates on different shift times for new vs. worn vs. very worn?

 

[intheburbs]

The 6L80/90 were designed for operating temperatures of 190-200°F.

200°F is not necessarily "overheating." The "trans hot idle engine" warning comes on a little over 260°F. I forget if it's 262° or 265°.

100° over ambient is typical if everything is functioning properly, so you can expect to reach 200° in normal driving in warmer weather.

 

[NickTransmissions]

Yes the 07-14 runs transmission line to radiator, then to the aux cooler if equipped.

I have a 2012, 209k miles, no aux cooler yet, and it seems to get right up around 200degF as well.
Doesn't take 1.5 hrs to get there either!.. New radiator, fresh fluid.
I might try reducing or zeroing the slip in tune. I've already removed TCC lock in gears 1-3.

@NickTransmissions any general estimates on different shift times for new vs. worn vs. very worn?

A second or less is what I typically see in a healthy transmission, anything more than 2 sec prob indicates wear.

 

[donjetman]

The only reason I know something is wrong with it, is the digital temp gauge had reached over 200°.

My 07 Denali w/6L80 and factory installed medium duty (rpo KNP) cooler always runs 80-100* over ambient. If its 110* outside tranny runs 190-210*. This is normal and Dexron6 can handle it. When I have any question(s) about atf I call Tom Johnson at JG Lubricant Services. He's a retired GM/Allison fluid engineer. I also use their services for my used atf analysis.
https://jglubricantservices.com/

 

[blackelky]

Yes the 07-14 runs transmission line to radiator, then to the aux cooler if equipped.

I have a 2012, 209k miles, no aux cooler yet, and it seems to get right up around 200degF as well.
Doesn't take 1.5 hrs to get there either!.. New radiator, fresh fluid.
I might try reducing or zeroing the slip in tune. I've already removed TCC lock in gears 1-3.

@NickTransmissions any general estimates on different shift times for new vs. worn vs. very worn?

I'd add the factory trans cooler. All in it was like $300 with new trans lines everything bolts right up. Just order the knp transmission lines.

 

[mikez71]

I'd add the factory trans cooler. All in it was like $300 with new trans lines everything bolts right up. Just order the knp transmission lines.

Purchased, just not installed yet!

Certainly can't be taking 2 seconds to shift.. Will have have to log shift times..