I did get the green o-ring changed and it was there when I started.There's no spring tension on that valve train, unless you install Transgo's TCC valve or the Fitzall valve (or Sonnax's oversized valve but that requires a reamer to wallow out the bore to fit their os sleeve/valve kit).
Besides, that's not why the 3-4 burned shortly after rebuild.
Yes, Im wondering if you forgot to install the green o-ring at the base of the forward drum so you're starting off in 3rd instead of 1st gear - that's exactly what would happen if you leave that o-ring out...Was it there when you took the forward drum apart?
It looks like the check-ball that goes into the 2/4 Servo was not seating. I poured ATF in and it flowed both into the Servo and the main housing. A tap with a punch and hammer seems to have fixed the seating. (Your thoughts on if this is ok way to fix?). I even believe a piece of trash came out, making me feel better that 1) this was a legit problem 2)Wish I had checked this the first time thru.