3rd gear help

my 56 chevy 3600 has a 235 six cylinder and 3 on the tree, runs great but pops out of 3rd gear at any given time. If I hold it in gear it runs fine, but if I don't I get the occasional pop into neutral. Any ideas what I can do to avoid this, any help will be appreciated thanks for your time. George

 

Pull the transmission and rebuild it. The problem you are having is classic syncronizer wear.

Ray

 

Probably time to rebuild the trans. Worn synchronizer, bearings worn and gear endplay can all cause the problem. It is an easy trans to fix and the parts are not real expensive. Take the side cover off and see how much wear is on the shift fork for third gear.

 

The problem with a 3-on-the-tree that its hard to bungee cord the shifter to something to keep it in gear, works great on old 4-speed tow trucks.

I agree, gotta take it apart to see what's what. They're pretty easy to go through unless one of the hard parts has gone kablooey.

Bob

 

The longer it has been jumping out of gear, the better chance that the small teeth on the syncro hub, and the inside of the input gear, are worn at an angle. These side faces of the teeth, need to be 90 degrees to the shaft, not angled.

If you do pull it apart, look at those small teeth faces.

 

Ditto, the synchro.....They did make a "heavy duty" replacement, Supposedly for taxi and police vehicles. I always had an extra one handy....My 57 went thru quite a few of them. I think you'll find the 2-3 shift fork will be well worn as well.

4TTRUK