Ok, so I bought the pressure piston kit and installed it- The directions are VERY good, with the exception of not being super clear that the split orings go on first with some transmission grease, then the rubber Orings go AROUND them to squish them into shape when in the freezer.

Here are some pics and steps:

Step one- remove the pan and the front valve body assembly:



Its the part of the valve body on the right, no need to remove the whole valve body, just the font part.





Where did it go?



Here it is with the plate removed (CAREFUL!!! IT WILL SPRING OFF) Have a friend hold it with you while you remove the screws.

Put the split rings on the NEW piston with transmission assembly grease, then put the provided orings DIRECTLY over the split rings. Next, put in freezer for a couple hours to "set" the slipt rings in place so they can fit in the bore.

After freezing for a bit, remove the RUBBER orings and slide the piston in the bore, being careful and avoid snagging the split rings, which could ruin them.

Next, put the new spring in and gently press the plate into place with a plastic clamp or zip ties, then bolt down to correct Nm.

Put it back together and take it for a test drive!

Here is my old piston if anyone would like to see:





There were a few scratches-


It is my guess that the transmission was rebuilt with a new old-style A drum which consequently failed after some miles because of the pressure valve. The clutch plates were new-ish looking and the ATF was a golden brown. Also had a new looking TC. I wonder if the person I bought it from had the tranny rebuilt and it blew shortly after, causing the sale of the car.