I just re-built my TH400 BB stage 1 trans. I took out the SP set-up that was in it when I bought the car. I used a low milage core, for the front pump, input shaft and drum. The 1-2 shift is great but the 2-3 feels like it slides in, but doesn't slip once it is in 3rd. I've tried a different modulator, no better. I was wondering if the valve body was different on the SP ?? Any help or suggestions would be greatly appreciated. This is the first SP set-up I've removed, but I have rebuilt 7-8 400's with no problems. Thank's in advanced. Phil.
Phil, I'm no trans expert but the SP valve bodies were different for sure. They tended to get the trans into direct drive sooner and they had no 3-2 valve, which means you only have a full throttle kick down. Read here: http://www.buickperformance.com/SPTrans.htm
