Working on an friends 07 grand prix 3.8. About a month ago transmission was slipping and slamming into gears, they brought it to dealer and had the tranny flushed no filter change. Did not help the issue. They brought it to me, I found huge mouse nest on pcm in airbox with 1 wire for the fluid temperature sensor chewed all the way in half, and a half dozen other wires gnawed and shorting together. Cut out bad wire sections one at a time, soldered and shrink tubed in new wire, rechecked continuity. Seems when the wires were touching each other the tft sensor got burned up and the tcc solenoid was damaged as well
Pulled side cover and replaced internal wire harness, tcc solenoid and tft sensor. Reinstalled cover, topped up fluid, reset TAP values and test drove. Seemed to resolve the issue, however the 2-3 shift was a bit firmer than I thought it should be, and a max adapt long shift code came up. I figure clutch pack wear from driving with damaged wiring is the reason for this code. Would this be a good assumption?
Fast forward two weeks car is back in my garage, wont shift. Put in drive it accelerates normally until about 30mph then seems like the transmission lets go, engine revs but no power sent to wheels. After ive coasted to about 20 mph it will hook up again until 30 mph then let go. Fresh fluid from flush is still nice and red, doesnt smell burnt, level is perfect.
Hooked pressure gauge up, ran through line pressure test from shop manual, regulating amperage to pressure control valve, readings are within spec. However when i drive the car with gauge attached i see when i hit 30 mph and the tranny lets go the line pressure spikes above 200psi and then bounces from 180 to almost 300 very rapidly.
can anyone give me any pointer as to what to do next?
Thanks
Will
