Posted By: Dusty 1937 three speed jumps out of gear - Wed Feb 25 2015 08:24 PM
I have been asked to fix a gearbox, It was hard to get into second and would jump out of that gear.
I've pulled it apart , and another 3 g/boxes and everything is worn.
I find it hard to tell what actually causes this defect as I have no new parts to measure.
For example , what end float should there be on the main shaft?
How thick for the 2nd gear thrust washer?
Who might have new syncro hub / gears etc?
What else might cause it to come out of gear?

Thanks for your thoughts.
Posted By: Dusty Re: 1937 three speed jumps out of gear - Sat Feb 28 2015 03:00 AM
Still struggling with a solution for this issue .

Surely someone has found a fix for this (now common) wear item.
Posted By: Wally / Montana Re: 1937 three speed jumps out of gear - Sat Feb 28 2015 03:42 AM
All I can say is I had a '39 Master Deluxe car 50 years ago. Yes, half a century!

It had some kind of vacuum assist for shifting up-gear but the dang thing would help it shift out of gear to neutral when I backed off in high.

Not much help here.

Posted By: GWWirth Re: 1937 three speed jumps out of gear - Sun Mar 01 2015 03:13 AM
When I found a place in Portland OR who had an older guy who knew all about the three speeds. He indicated that when the syncros are worn they will pop out of gear. He indicated the only fix is to replace the syncros. They don't make these anymore. He rebuilt mine because the difference between the parts and him doing the work was 100.00. He said he had hundreds of the transmissions.
Posted By: Bogart's Truck Re: 1937 three speed jumps out of gear - Fri Mar 20 2015 02:05 AM
I know that the 40-52 three speed will tend to wear the third gear teeth and that will cause the transmission to pop out of gear. The wear is the tapering of one end of the gear teeth slightly. The solution is to replace the part but that part is becoming rare since it often needs to be replaced. I imagine the parts for your trans will be even harder to find. This blog below has a good picture and explanation.
© The Stovebolt Forums