2004 Pontiac Grand Prix Trans Problems

Yes, I have a suggestion. Take it to a transmission shop and get it diagnosed right away. Transmission problems don't go away or heal themselves with time. They only get worse. Transmissions are grossly expensive to repair or rebuild so if you can head off a problem before it gets worse you will likely save a ton of money.

if you scan the car you most likely have a P1811 code set (maximum adapt long shift) this sets and gives you the harsh shift as the computer defaults to maximum line pressure and removes any shift adapts ( a slower application of the clutches to improve shift feel) most times this happen because the pressure control solenoid is jamming a common problem in the 4-t65-e trans, the trans is most likely fine and the pc solenoid just needs to be replaced