Transmission pops out of third gear

[Charlie Stephens]

Originally Posted by nkaminar

The shims should be the same thickness as any gasket between the flywheel housing and the bell housing. No gasket, no shims.

I think you are grasping at straws and a transmission rebuilt is in the cards. Start with the shift tower to make sure the detents and plungers are all OK. Check to see if the fork that does the shifting is not worn excessively. Then look at the cogs that mate high gear together. If the cogs are worn then thay can force high gear out of gear. The wear can act like little ramps that force movement under load.

You forgot the part about "No gasket, oil leak".

Chagrin Stephens