Hello,
so I've been messing with the transmission and the valvebody(doesnt shift to 2nd gear shifts 1-3 even though its supposed to be a 2nd gear start 600 sec and Band is OK and so is the piston), and still cant figure out whats the problem, everything seems all right no debris enywhere even in the filter and the valvebody. We looked again at the B1 piston and it adjusted itself so there is pressure and it works, the band is seated OK thrust body is like new.

...But there is one thing I still didnt check and that is reaction valve under overload protection switch which is on the other side of the B1 band and is supposed to work to hold B1 band compressed. It even has pin that holds the band from the other side oposite the B1 piston.

So my question is how the hell would this part brake and how would I check if it works or not? Or do I have to buy a new one to know for sure? Why wouldnt any manual point to this as a possible culprit when its evidently as imporatnt as B1 piston???!?!?

I never read anywhere that this part broke just overload switch leaked or something there leaked.

EDIT: could the pin get misaligned by any chance resulting in slipping band?

Does anyone have any experience with this?