is there a problem with the shudder in the transmission
05 cadillac cts 2.8 has a problem with a shudder in the transmission when you try to maintain speed between 35mph and 60mph. It usually shifts hard when it starts to shudder. I think they have been trying to fix the problem but can't.
sounds like you have some band slippage, I would take it to a tranny shop
I had the same problem with my Crown Victoria, I had the fluid and filter changed and it solved the problem.
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