drive or OD
http://www.transmissionpartsusa.com/...-007775441.htm
You have to remove the valve body and mod it by drilling a hole between two passages; so there is no going back.
WRT mentioned that the 700R4 definitely had the overrun clutches engages in D3 for all gears. I suspect that GM changed this in the 4L60e to "soften" the automatic downshifts in D3 as the car was slowing. I think we would all prefer the tighter feel of having the overrun clutches engaged in D3, plus it puts less strain on the forward sprag.
IMO if you want the best shifts and strongest poss. trans then shift the gear manually. Then the overrun clutches are always on enven according to your chart.







