Pontiac Repair: pontiac montana noises, p1811

Question
Hi, my van has been making a hard thumping noise when changing gears. Only it doesn't do it all the time. What could be causing this?

Answer
Hi Lynda:

has any service engine soon lamp come on? have the van scanned for coides at one of the big box auto parts stores chances are that it has a p1811 code stored in the engine computer and if that id the case and it just started doing it all you will need is a pressure control solenoid in the transmission. It controls the amout of pressure apply pressure for the gear shifts when it goes bad the shifts are firm and hard. It's not a bad as it sounds the tranmission doesn't need to come out of the van to be fixed. good luck :-}