[tooski]

I am resurrecting a TH350 that lost all the gears (except park and neutral).
I have it disassembled up to the center support and low/reverse clutches.
The forward and direct drums are disassembled.

The reason for the failure became evident when I pulled out the input shaft and the two drums did not come with it. The splines at the bottom of the forward drum were in pieces.

I believe the cause of this was the bone jarring 1-2 shifts when not at wot. The wot shifts seemed fine.

Before I put this trans into service I installed a B&M shift kit set to high performance as to RV/towing. I do not know its previous history, but items made it evident it had been opened up.

There were flat steels instead of the wave steels in the intermediate and forward clutch packs. The direct drum return spring pack has 12 springs instead of 17. The forward drum return spring pack has 16 springs instead of 20.
Preliminary inspection shows the steels and frictions to be ok.

Would any or all of these cause the violent shifts? Is there anything else to look at, maybe trans fluid pressure?