[Mark68]

I have a '68 with an M-21 and been having problems with it jumping out of 4th gear while off the gas. I was told that the first thing to do was check the adjustment bolt for 4th gear. Can anyone tell me if I should be looking at the front or rear bolt and what exactly is the adjustment procedure? Any help would be greatly appreciated.
Thanks,
Mark

[JodysTransmissions]

The front bolt on the shifter body is for second and forth gear, the rear bolt is for first and third.

Since you have trouble with forth gear.............

Engage the shifter in forth gear
Turn the stop bolt "in" until you make contact
Back "out" the bolt one full turn from your contact point

Also, double check second gear and make sure you have one full turn out from contact

[oger]

If it's not the shifter it usually is too much end play on the input shaft or the front bearing is getting loose. It's not a major problem to fix either.

[m21man]

sometimes check the shift boot, mine was doing the same thing turned out the shift boot was putting the shifting in tension a bit and it would pop out. I made a slight modification in the boot and all was fine.