had tranny rebuilt by local shop while I was busy with wrenches on the v12 - when the 4 speed went back in, first test drive was a heartbreak- tranny popped out of third when I would lift slightly-
took the gearbox back- they redid it and reinstalled- third was fine- popped out of first
took it back- rebuild - reinstall - yesterday's test drive.....

POPS OUT OF THIRD (again)

not my driver- shop is willing to do the right thing, again- but I am extrememly curious as to whether anybody has been thru anything remotely like this or has the knowhow to get me headed toward a solution- thanks all

 

I had exactly the same problem, popping out of third on the overrun after a rebuild ........ box now back at shop for another rebuild.
How did you resolve the issue?
I have to pay every time the box is removed and refitted, and the shop is not very gracious about redoing a rebuild!
They are saying it must have been like that all along, even tho I have had the car since 3k and 1974

 

Most common reason for popping out of gear is Shaft Alignment! Change front input bearing on main shaft, change center needle bearings between shafts and be sure to change rear output bearing for mainshaft as well. Even with worn synchros, worn gears and worn shifter gate if the bearings are new and in line a trans WILL NOT pop out of gear !