I went through the EXACT same routine you did with a guy I had used for 15 years
for all work on my transmissions. I finally had bruce make me a trans with the
blessing and help of my local guy. The local guy refunded ALL of my original $$$ and
did the install of Bruce's trans for nothing. The point is most mechanics are proud of
their work and will be honest if they know they can't help. The quote from my guy was
"It beat me and I'm sorry for not being able to fix it.". VERY PROFESSIONAL!
My trans now works fine except for some part throttle hunting around 22 mph from
2-3 that I can't get rid of and some very hard 1-2 shifts at light throttle. Yeah, it cost
me 2 grand + but if you wanna play you gotta pay.
Go back to your trans guy and talk it out. He will probably do all he can to make it
right.
Vince