The ball wont seat unless pressure drops below certain thresholds; however, over the years, many builders have found it will seat when it isnt supposed to as a result of variability in line pressure characteristics across individual 700R4s so many will decide not to mess with keeping it in.Hey Nick,
In your vids you make reference to the TV exhaust check ball and recommend not leaving it out in case the cable snaps. Makes good sense to me! While I was servicing the tranny and replacing the TV cable I noticed the TV lever has pin on it that pushes against that check ball as the throttle valve is being pushed in. When should that pin start to push that ball up? My TV cable is adjusted per the factory service manual.
The reason I'm curious about this is late harsh 1-2 shift when just easing off from a stop. If I mash the throttle say 40% then the 1-2 shift is normal and has me wondering if someone ground that pin down some. How much is the line pressure boosted when that ball is on its seat?
All that said, the TV check ball is prob not your issue, more than likely you have too aggressive a 1-2 shift calibration that's producing the late/harsh 1-2 upshift only at part throttle. You could always drop the valve body and remove that check ball if you dont want it in there...