3 speed manual transmission help

[vetnat]

Hi. 3 on the tree. My truck sat for close to 30 years, because PO put a different steering column in, and would not shift gears after that. Or so the story goes. Just got done rebuilding and installing a 1967 column, with the collapsible shaft. Adjusted the linkage and now it shifts gears, yay! Unfortunately however, the transmission does not seem able to go into third gear. I still need to run new brake lines, so truck is not drivable yet, so not 100% sure third gear isn't working, but it "feels" different than the other gears.

It feels the same whether using shifter on column, or manually moving the levers and linkage under the hood, or actually moving the levers on the trans itself while lying under the truck (with linkage rod disconnected). Reverse, first, and second gears all feel like they are engaging. When shifting into third gear, the throw is shorter, and just stops with a hard thunk, feels like something inside is stopping it from going into that gear. Any ideas? I'm not at all familiar with transmissions, but I do have a shop manual No troubleshooting in manual that applies to this situation. Truck is 1961 GMC half ton with 235. Thanks.

[lumpy63]

with the truck on jack stands , try spinning the drive shaft by hand while moving shift lever into 3rd gear. Everything has to line up inside trans, synchro's etc . you cant just force it into gear especially if its been dormant for awhile . Synchro's can stick on the gear hub and cause non shifting problems.

[vetnat]

Great! That sounds do-able, and inexpensive. Will try that. Thanks.