Hello All,
hope I am doing this right. I have a 2016 Sierra, 5.3 4x4 - tow package and heavy haul capacity, Lately, the transmission has been suddenly not up shifting past fourth gear. the engine RPMs will go over 3000 to make gear changes from a stop for gears 1 thru 4. after that no upshifts just a high RPM engine. The trans fluid is clean, trans temp is 190-195. No trouble codes or check engine lights. Tomorrow AM the truck will run perfectly and then it will act up on the way home in the evening. It has done this 4 days in a row. I have unplugged the negative battery cable for 15 minutes and the truck will operate fine that night. The problem returns the next day. There is also no manual upshift either past 4th once this issue starts to happen. The truck has 80K on it all highway miles. Any ideas would be greatly appreciated.
Mark
hope I am doing this right. I have a 2016 Sierra, 5.3 4x4 - tow package and heavy haul capacity, Lately, the transmission has been suddenly not up shifting past fourth gear. the engine RPMs will go over 3000 to make gear changes from a stop for gears 1 thru 4. after that no upshifts just a high RPM engine. The trans fluid is clean, trans temp is 190-195. No trouble codes or check engine lights. Tomorrow AM the truck will run perfectly and then it will act up on the way home in the evening. It has done this 4 days in a row. I have unplugged the negative battery cable for 15 minutes and the truck will operate fine that night. The problem returns the next day. There is also no manual upshift either past 4th once this issue starts to happen. The truck has 80K on it all highway miles. Any ideas would be greatly appreciated.
Mark