I have been having problems with my auto tranny. When I coast to a stop the tranny will surge/shift hard and then stay in 2nd gear. So when I take off again the rpms go up to 2500 and the truck barely moves. Anyhow I have taken the thing in 3 times now and the dealer says they cannot duplicate the problem. They replaced the actuator and it worked for about 100 miles and the same thing happened again. Any ideas? Similar problems. This is really a PIA, I almost got hit making a left turn because the truck just creeped along.

 

it's making me wonder if youve balloned the torque converter.

this is on the 48RE with a Cummins right???

if thats not it I would say a solenoid is gone, or a check valve in the coolant lines has gotten clogged.

 

forgot about the 48RE, the only two solenoids on the 48RE are the OD and TCC, everything else is pressure regulated, so either it still stands, TC balloned, or you have a clogged govenor or check valve.

 

Yes, it is the Cummins. The truck has 2000 miles on it and the problem it intermittant. Once the surging starts it happens until the truck is left overnight. The rest of the time it works fine. My guess is that it is not kicking back down into first/second.