BorgWarner R-10 Overdrive Rebuild
 

I just finished assembling an R-10 overdrive unit and accompanying three-speed manual transmission for my 1951 Ford. Other than needing three sets of hands, the build went well... at least I think it did.

Now that the overdrive unit is together (along with the transmission), I can't seem to turn it by hand. Does it take an inordinate amount of force to turn the main-drive gear through the overdrive and out? It feels locked up and I don't want to force it. I've tried it in various gears, with the manual lockout engaged and disengaged, I've tipped the whole unit one way and then the next to ensure the pawl slides into and out of engagement but I still can't tell if something is wrong. Is there a common thing to miss when assembling these units?

For this build, I cleaned and inspected all the parts and everything looked very good and moved/engaged smoothly. I also installed a new ball and roller bearings, new blocker rings and synchro parts, a new main shaft and a new main-drive gear.

Re: BorgWarner R-10 Overdrive Rebuild
 

I have had a roller slip out where the input shaft meets the output shaft and jam up the works. Also make sure you have the forks engaged properly and you're not locked in two gears.

Re: BorgWarner R-10 Overdrive Rebuild
 

With the two control levers in neutral (middle) position, All that turns is the input and the cluster gear. Will it turn in neutral? If not then it's in the front section. If it turns in neutral but won't turn in any other gear, then it is likely in the rear section (OD).

I use a rubber band on the sprag rollers (free wheeling unit) when installing the tail section. The rubber band will be pushed out of the way and will eventually fall off but it won't hurt any components in there if it gets caught up.

Re: BorgWarner R-10 Overdrive Rebuild
 

UPDATE: OK, after ruminating on this issue and spending a little time tinkering with the assembled transmission, I've discovered the problem. It turns out, the governor drive gear does not mesh with the corresponding gear on the output shaft! The governor that came with the transmission is not the right one for this application. Somehow, I was still able to (easily and without forcing anything, I might add) install the governor. When I removed the governor, everything in the transmission turns smooth as silk. Thanks for the input, guys! I'm so glad this was an easy fix.