904 Tranny not shifting in drive

I can't imagine a cracked piston in the front clutch would cause that cause if it were cracked it would not apply meaning you'd have no third gear or reverse. The front clutch has to be applied or it would not have high gear in any gear selector position. It sounds like a governor issue to me. I'd run a governor pressure test to see what it is. If it's too high it will start off in third gear but manual shifting will operate correctly. The pressure should drop to near zero (no more than 1-1/2 psi) in drive at idle with the brakes applied (not moving) and increase as the car takes off. I don't remember the governor pressures off the top of my head but it doesn't take a lot of pressure to make it go into high gear. The governor test port is the 1/8" port near the bottom of the extension housing. I have a picture of it but for some odd reason it won't attach. If you'd like a picture PM me with your e-mail address and I'll send it to you.