Thanks again for your help.
I have a 400 psi gauge around here somewhere or I'll buy a new one. At one time or another I think I've owned every tool ever made. It's keeping track of the ones I don't use very much that's tricky. I plan on going into the pump to check for scoring or just wear of the cover and housing. I also want to be sure the vanes are all good. Then, once I know the pump is healthy, I'll swap in the high rev priming spring. I assume it's a 10 vane. Pretty sure the 13 vanes weren't around back then.
As far as the harsh 1-2 shift goes, I'm pretty sure the builder used the TransGo method of the time, which is removing the 1-2 accumulator spring and installing from 1 to 3 washers instead to set 1-2 shift "firmness". With high pump pressure this translates into a crash bang 1-2 shift at low speeds. PATC talks about this and they offer a heavy 1-2 accumulator spring which they claim will reduce the harshness. They recommend the Superior/Fairbanks servo to ensure solid band engagement. I've been looking at this servo and the Sonnax billet servo. They each have advantages and weren't available when this trans was built. My trans may have the Art Carr billet servo now. We talked about it when the trans was being built. If you come across the billet servo you have, I'll take a look at it. I like the idea of the wide carbonite band. I want to find the funds to include it, with a new reverse input shell, in this repair.
I'm waiting to see the damage in the trans to decide which way to go with the repair. If the damage is isolated to the 3-4 clutches. I'll focus on that and maybe upgrade the 2-4 band and address a few other little issues. I may go with the overkill Smart Drum just because it's a long term solution to the 3-4 clutch problem($500, ouch). I am worried about the process of swapping turbine shafts. It may be worth it to pay a machinist to do the job for me. I'm thinking that if a had an oven set up close by the press, I could heat the drum up and then the shaft would slide in much easier. I'm not sure if the locktight green would agree with the heat though.
Once I save up the funds, I'll swap in a hardened billet turbine shaft and be done with it. If the 3-4 snap ring has popped out, this will help me with that decision. Do you know where I can get a good input shaft(no drum), besides PATC where they want $534 for it.