TRANS; DOES NOT SHIFT OUT OF LOW GEAR TILL 40 MPH. IF LET UP ON GAS IT WILL SHIFT, THIS JUST STARTED. FLUID DOES NOT FEEL GRITTIER
Does the fluid still have a red tint to it, or is it orangish? Has it been serviced regularly? The filters maybe plugged or the valve body solenoids have varnish in them. Is the check engine light on?
the trans was service by gmc 3 mo's ago the fluid is red. does not smell burn. was returning from a 600 mile trip. no over heat on engine. had a error code Po101 when I got to town. lite went out on it's on after driving for 20 mins in town.
P0101 Mass Air Flow below specs, shouldn't cause a trans shift problem, were you towing anything or loaded heaver than normal? You might try resetting the ECM by pulling the ECM fuses and waiting about 30 seconds, then putting them back in, this should reset the ECM back to factory then try driving it as you normally would. If that doesn't do it then you will have to use a live data scanner to see what is going on the the inputs and outputs to help trace down whether it is a electronics problem or a tranny problem. HTH
Two people in car w/luggage about 50lb.
Still try the ECM reset. Might cure the problem.
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