Bcalc

I know this is an old tread but was wondering if you ever figured out your issue? I have the exact same problem with a 700R4. I have changed the governor, servo, and valve body... I also put the sonnax throttle valve kit in (3/4 throttle). It still goes right back to 4th under very light throttle. It's all transgo parts with makes it automatically lock up in 3rd and 4th hydraulically (electronics deleted). 1st through 3rd lock up works great btw. Thanks!


update: I sat and thought about this issue after posting this. I decided to remove the servo housing with 4th apply piston after measuring housing travel. I had about .2 inches of travel, which is too much (should be .075 - .125). So I added a washer (.08 inches thick) between the E clip and 4th gear apply piston, then reassembled. Took it for a test drive and 4th gear goes in solid and holds like a champ. So getting pin length correct in the servo is a big deal! Hopefully this helps someone one day!