Thrust spacer wear in 722.3 trans excessive?
 

I've disassembled most of 2 722.3 transmissions (still have to do the clutch packs and planetaries) The two units have failed for different reasons, but one thing seems similar on both - the shims used to set the axial play for the K1 and K2 clutches on the input and output shafts have really taken a beating. A few are in pieces, most of the rest were burned, split or galled. I certainly don't know much about automatic transmissions (having only rebuilt 1 before), yet this surprised me. Is this typical for these units, or not?

NOT UN-COMMON at all! about 25% of the ones that I've have had a simular failure.

Thanks! any suggestions to minimizing a reoccurance of that? Use as few spacers as possible to adjust the play? Use mobil 1 or an oxidation additive? Set the play closer to the lower limit?