Sort of a problem solved already ... turns out it was the rubber boot around the gearstick causing the problem.
W57 in my racecar was fine before my crash...
Put it all back together and took it to Puke a month ago - it would pop out of 3rd gear whenever I lifted off the throttle???
Bugger! - did I bend a selector fork in the crash? Dammit!
Got my spare W57 and shoved it in the car.
Drove it around Puke yesterday... popped out of 3rd gear?
BUGGER
2 gearboxes with identical problem??
Picked Glenn (ez10s) and Ewan (10k20v) brains. Glenn looked at the plate that holds the gearstick in... it was fine.
Glenn says "looks like you have too many rubber boots on the gearstick"
Ewan has a play with boots and gearstick
He finds that there was a very slight pull on the gearstick when it was in 3rd gear... just enough to pop it out on trailing throttle.
Leave rubber boots loose and problem solved!
I had relocated the engine slightly lower than before the crash. This meant the boots were stretched a bit more than before.
Sure beats pulling good gearboxes to bits and not finding a problem!
Thanks Glenn and Ewan!
Ken