Pops out of Second gear

[pgeorgeson]

1966 IIa 109 2.25. Stock transmission with no overdrive. It goes into second gear fine and it drives fine (and there are no problems with any other gears), but pops out of 2nd if I hit a bump or sometimes when I abruptly lift off the throttle. Advice sought for diagnosis and repair.

[SafeAirOne]

First off, I'd check that the mainshaft nut is properly tightened. Then I'd check the shifter detents to make sure everything is hunky-dory. Then I'd hold on to the gearshift lever when I decelerated downhill in 2nd till I could examine the transmission closer, including the layshaft bearings and synchros.

I've been holding onto my lever for...6 years now.

[busboy]

If I remember right there is some play in the where the shifter can be tightened, it's not much but in my case was enough to totally stop it from jumping out of second anytime. I suspect my wife caused the problem by forcing the gear lever, why do I think this? She called up one day to say the gear lever had come off, she had actually broken/snapped it off just above the ball. It took a few years but I finally discovered a dragging/bent clutch disc was the problem, causing the gearbox to still turn over very slightly while trying to change gear.

[I Leak Oil]

I'd second Mark's suggestions. (except the 6 year part) Other than the mainshaft nut and the detents there really isn't much else you can check without starting to dismantle the box. The next item would be to remove the top cover and start checking the shift forks. After that it's a matter of putting on the scuba mask and diving right in. These aren't complicated by any stretch but make sure you have a manual when you go in.

[LdogRover74]

I have the same problem with my 1974 Series III except it is my 4th gear. Everything I researched pointed to a synchro problem. I am still looking into it but until then I use a bungee to keep it in gear on long trips.

[martindktm]

HAd a second gear problem and I had Wear on the shifting fork and the C clip holding the bunch of gears with the brass bushing had pop out. Almost the same symptoms as the rear shaft bolt.