Trans @ cruse control

[skorski]

My o5 with 100,900 mi 70% pulling 13,000 5th wheel. While pulling in tow hall at 62 mph in cruse the truck will maintain the 62 most of the way up hills . Just about 3/4 up it will shift down and bring me over the top. Now the problem I am seeing is the transmission stays in the lower gear. It will not shift until I knock it out of cruse. Won't do it on smaller hills. Please advise. Factory Auto With suncoast valve body no inhansments.

 

[cerberusiam]

Downshifts with TH and CC almost always require CC cancel to get an upshift. Its gets more pronounced when the VB is modified. The CC cause too early a downshift on most grades anyway and kills fuel mileage, turn it off.



The CC is trying to return the truck to the set speed without consideration of the rpm difference between drive and OD. The load and rpm exceeds the ECU set point for an OD shift. Then again, sometimes not. Its an anomaly in the programming that causes it. Not really worth trying to address considering.

 

[skorski]

Thank you cerberusiam I was afraid the transmission was on it's way out, or maby just looking for a good excuse to rebuild ha ha .