I have recently rebuilt a Series 3 suffix B gearbox, with needle bearings reverse gear, all bearings were replaced, rev gear, bearing and shaft, 1st/2nd synchro, mainshaft bushings. Everything is fine otherwise, but reverse gear keeps disengaging once it starts to take up any load. If i try to hold it in with my hand it still kicks out with a heavy crunch.
On repairing the box I notice that the reverse gears keeps biting on 1st/2nd synchro gear, and there are visible signs of contact with these 2 gears as chucks of each are missing.
A guy advised me once to replace the rev gear needle bearing with a bushing specially made in a machine shop.... this did work but the bushing did not last long and the rev gear starting bouncing out again.
Any suggestions anyone????