The Stovebolt Site Forums The Shop Area Driveline Muncie 319 stuck in 3rd gear

After 3 years, I am finally able to drive the 1959 I inherited from my dad down the highway. Unfortunately, it is now hanging in 3rd gear. It is not the linkage because I disconnected it, and it will still not move. Eventually, I can keep working it and get it out. It has a 319 Muncie. The last time it did it, I pulled the transmission and removed the side cover. The 3 speed clutch will not slide. Somehow, I kept messing with it and got it unlocked. I was able to shift to reverse, 1st, and 2nd but when I went back to 3rd it locked again. Dad had the transmission rebuilt before he put it back in the truck so I don't know if there is something wrong with the re-assembly or if something has broken. I don't expect to be able to fix it myself, but I would like to know if anyone has an idea what is happening. Is it possible that the clutch can slide too far forward, causing it to lock?

thanks
curtis

Curtis - Just to confirm your "319 Muncie" is the three speed w/overdrive, yes???

319 only is a 3 speed

BD - The SM319 is a 3 speed with overdrive. The SM318 is the standard 3 speed non-overdrive transmission. Main "3 speed" portion of the transmission is basically identical, but the addition of the overdrive does entail some differences between the two models.

The engagement part of the Syncro assembly is held in with an internal snap ring
on each end. It sounds like the 3rd gear end has disengaged and is locking up and causing
the problem you described. If so it will require a tear down to determine the damage caused.
It likely will need that component replaced or rebuilt.
Fred

Yeah, I think thats why he said its a 319 to start the thread?

Yes it is a 319 overdrive..

Thanks for the explanation. I can see the front and rear snap rings so at least they are not chewed up somewhere. The repair manual does say a poorly fitted ring will not permit proper syncronizing of gears during shifting. Out of curiosity, what is the energizing spring for?

The energizing spring corresponds with the engagement nubs on the syncro to help
hold the matching components in place. In many cases the brass rings which are pressed
in and staked into the small holes on the drum loosen up and move outward which causes
either popping out of gear and/or the problem you describe.
Fred

I found someone to look at the 319 and forwarded him your explanation. He said that you are correct. He said there is wear that is causing it to lock up. Do you know of a source for any of the parts?

Curtis - If you are just needing the 2nd-3rd clutch assy w/synchronizers, there is a pretty good looking used one here on eBay at present. There are two known GM#s for this assembly. The earlier is GM# 3733889 Clutch assembly - synchronizer: 2nd-3rd speeds. The later is GM# 3774720 - same description, which is actually listed as replacing GM# 3733889 before this later number was retired.

Borg Warner made and sold replacements under Part# "WT266-2.5", but I couldn't find anything offered on the web.

If you don't wish to pursue the ebay offering, put an ad up in our Truck Parts Wanted Swap Meet forum to see if there are any Bolters that may be able to help you out. Good luck.

I have had that assembly rebuilt by Anaheim Gear in Anaheim, CA. 800-477-1103
You will need to send them the part. Should be under $200 including shipping.
Fred

Update. @rfs56trk explained what the issue was and sent me a link to a part on ebay. After almost 8 months, I had to go get my transmission from the person who had it and install the part myself. I was able to drive do a few laps around the neighborhood and it shifted well. Thanks to the Stovebolt forum for helping me move forward on this project.

Curtis - Sounds like you purchased and installed a replacement 2nd to 3rd synchronizer clutch assembly to resolve the problem. Glad you were able to resolve the problem and thanks for coming back and reporting on the solution!

Sorry, looks like i got it mixed up. You sent the link to the part, and I was discussing with rfs56trk in private messages how to rebuild it.

Thank you for helping me get the truck running again. Unfortunately, it has been too hot to get it out of the garage and enjoy driving it.

No worries. We all work to share what we can as it's just what this community is about!

I'm with you on "...it has been too hot..."!

Ditto here as we are on day 8 (or is it 9?) of real temps between 95-98 and heat index well over 100. Wouldn't be so bad if the humidity wasn't at the top of the scale too.