6L80 rpm increase in cruise.

[11bDad]

Noticed that if I activate Cruise Control @ 70 mph and I'm turning 1750 rpm in 6th, my rpm will increase by 250 within a mile. This is on very flat road, and it doesn't do it all the time. Truck has 12K miles and the torque converter, pump, and TEHCM were replace at 10K miles. Weird thing is if I am running 70 in 6th, and make it downshift & run up and shift into 6th, and then hit cruise when the rpms drop, the rpms remain stable. I've added a 22K btu Tru Cool transmission cooler, and eliminated the thermal bypass valve, so my temps are what the pre 2014 trucks are seeing. I would think if the converter isn't totally locking up, it would cause a temp increase, but temps are good. This transmission has been a pain in my a$$. What do you folks think?

 

[newdude]

How many miles on the truck now? If you are still under warranty, you may have shot yourself in the foot getting it covered by adding that aftermarket cooler and deleting the bypass valve as they can turn around and say that your mods caused a part failure (if that is what is going on). Does seem like a converter lockup deal.

[11bDad]

The cooler was on there when everything was replaced. The bypass can change back to stock configuration in 20 min., and I'm friends with the Service Mgr. Mileage is my original post. Tranny work was done at 10k miles and there are 12k on it now.