The PWM/TCC solenoid can be unplugged & have no effect on reverse whatsoever.
If your transmission does not engage reverse then there are 3 likely scenarios:
1. the transmission fluid is low
2. there is excessive wear in the low/reverse clutch assembly
3. there is insufficient system pressure due to other mechanical wear/internal leakage
Reverse is an entirely mechanical function, on this, and most other transmissions of the era.
Positive results gained by performing the described repairs can be attributed to either;
A. Correcting a low transmission fluid level
B. Increasing the viscosity of depleted/sheared atf
C. Improving the friction coefficient of incorrect/exhausted atf
I'm all about DIY guys, but this is silly. To the OP, go to howstuffworks.com, or better, atra.com (automatic transmission rebuilders association) & do some research.
Torque converters do not "grip", they are toroidal couplers: Two fans, facing eachother in a fluid medium. TCCs are irrelevant to the operation of reverse & until the late seventies, did not even exist in everyday automotive applications. PWM TCC's came about as a solution to clutch lock-up "BANG" & the tendency towards "on/off" solenoids to stick "on", resulting in stalling when coming to a stop.
I was referred to this post by a customer that had me install a TCC solenoid in his E46 328i. I thought he was trying to address the more common SES light fault associated with a failed TCC. Little did I know.
Look. I'm not bashing here. There is nothing dangerous posted. i have read dangerous DIYs before. No one is going to make their car any worse if they follow your instructions carefully. Your write-up is exquisite. It's just wrong, is all.