[gregory5000]

I have a 2002 Olds van and the transmission is showing a p1811 code. That is a code that is set when it takes to long to shift and then it ups the pressure and you fell a hard shift. I have a good friend(my wife's cousin too) that is the service manager at our local GM dealership. He pulled the code for and I asked him would changing the fluid help. He told me not to even think about. it has 161K. He said that if I changed it, it would start to slip. I have never changed it so that is why he said not to. It will clean the clutch disc and that why it would slip.

I think it would be OK to change yours.