VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 48 jumping out of 3rd gear

I've done a bunch of work to my 48 Fleetmaster including: Elimination of the Vacuum shifter with a conversion kit, and new side engine and rear transmission mounts. The shifter seems to work fine now, and, the PO indicated that the tranny had been rebuilt. However, she still jumps out of 3rd on me occasionally if I'm running 50 - 60 MPH on the interstate. One thing I notice is that the gearshift lever travel to get her in 3rd seems excessively long. When I pull her down in 3rd, I feel what seems to be a detent, but, then I have to pull the lever down a bit further to actually get her in 3rd. Could the shift mechanism in the tranny be put together incorrectly? I'm thinking maybe the detent ball and spring are in wrong somehow? Replacing the mounts helped the problem a bunch, but, didn't totally eliminate it. Appreciate any advice on where to go from here.

Regards:
Oldengineer

Maybe pull the side cover off the transmission and take a look. I'd look close at the 2-3 shifting fork to make sure its not cracked, broken or worn excessively. Don

Don has given you good advice.

I had the same problem with my 41 years ago. It wouldn't stay in drive (3rd). I don't know for sure but one thing I found was that the shifter was excessively worn (I tossed some other parts in whist I had it apart.

One thing to consider, it probably get worse soon.

Why don't you suck it up and take the transmission out. Check it out real good. Replace whatever needs it. Repair the vacuum shifter and toss that aftermarket junk that needs a long throw to shift the gears. If you need something to repair your vacuum setup, give me a shout. I've got a several in different states of condition from NOS to well used and can probably help.

Best,
Charlie

I would continue to readjust the linkage. You maybe as little as one turn off. Adjusting linkage is a whole lot easier than pulling the transmission, etc.. Good luck, Mike

P.S. Please post what finally solves the problem.

Thanks guys for the advice. I'll try adjusting a bit more first. I've got to pull the side cover off sooner or later because the shifter shaft seals leak gear lube. Then I can check the condition of the shifter forks.

Regards:
Oldengineer