I have a 1997 GMC Suburban. The transmission was rebuilt about 1200 miles ago. I am now getting the harsh 1-2 shift and P1870 code. I have done the research and know I have a valve body issue. I have found a brand new valve body that fits 02-08 4l60e. My question is beside the force motor needing to be changed will the 02-08 valve body work on the 1997 model. If so which gasket needs to be used? We installed a new universal separator plate during the rebuild.

I think you wull find this is a different valve body, check the parts interchangeability with a GM dealer, no?