The Stovebolt Site Forums The Shop Area Engine Shop OD Tranny ID Help

I've got a chance to buy an OD tranny from a 1958 Chevy(thats all he told me) with everything(so he says). Comes with the clutch, flywheel, starter, cable set up. etc. for cheap. All he's been able to provide me with so far is a few numbers from the casting on the side of the case. It's marked with the numbers 7437357. If anyone has any info to help me make a determination if it would work in my 64' with the original 230 I'd appreciate a shout. Thanks.
I have some pics, but don't want to tie up the system unless you need them, and I'd be happy to send them to whoever needs them to help. Just send me your email address and I'll correspond with you. Thanks for the help.
Tramp

Does the transmission look similar to this one? This is my Borg Warner R10 3 speed w/ OD: http://rides.webshots.com/photo/2288361650100720268ZocgBA

This is where the casting numbers are on it that says what it is: http://rides.webshots.com/photo/2225115630100720268PgsrTl

That's on the same side as the solenoid and the shift levers on the tailshaft housing.

Drew,
Thanks for the shout. From looking at the pictures, it appears I may have FINALLY found my OD tranny. H'es going to check the casting numbers for me today now that we know where to look. Comes with the bellhousing, clutch, cables, etc. for a Franklin. I'm headed out of the house this a.m. for the first car show of the year(as a spectator due to not having the truck painted because of the rains)and Monday a.m. heading out to pick up the tranny about 50 miles from here. I appreciate the help. Let you know what comes of it after I get it home and clean it up.
Tramp

The overdrive section used by Chev Was a Borg Warner that was used by all cars and pickups of that era. The front section can either be GM or the heavy duty one was a Borg Warner front section. Both are good. Make sure you get the entire setup. The relay that is on the firewall sells for $75 to $150 on eBay. Chev used a kickdown switch mounted on the carburetor. Ford and others used a a kickdown switch under the accelerator. The wiring is the same. Don't waste time before the guy changes his mind.

The overdrive as used by GM was only used with their own transmissions, they did not offer it with the HD Borg-Warner trans. '55-'66(?) would be the SM318/319 non-syncro first gear, later ones used the SM326 sith the syncronised first gear.

Chev used a T89 as a heavy duty option. They are very rare. I have one that I plan on putting behind a 302 Jimmie. I have been working on Ford overdrives for 45 years and the GM has much in common with the T89 Ford used, but the bolt pattern on the transmission fits a Chev clutch housing. I don't think they ever used the T85 or T86 that Ford and others used.

Can you tell me if the Ford version is available at swap meets, etc? I am considering an overdrive but would like everything else to look original(steering column/three on tree)

Would the 3 speed overdrive from a 69 GMC be a SM326? If so, is it the same as the one for Chevy?

Thanks!

I think you've got it right. This link on rebuilding the OD seems to imply that an OD for a sm319 or sm326 are one in the same.

http://www.classictruckshop.com/clubs/earlyburbs/projects/how_to.htm

LG

I have some questions about how to shift it then. The article mentions holding the release button while shifting into second. With a three on the tree I'm going to need an extra hand!!

6Pac - better to read about the correct operation in the manual [should be in your 60's manual as well], there's no "holding a button" involved

Bill

The article may be referring to the kickdown switch. It was very common to replace the kickdown switch with a toggle switch on the dash to be able to control the od instead of the governor doing it. That way you could actually have 6 forward gears. You can preselect the toggle switch and then shift with the stick. You don't need both hands at once.

Would the 3 speed overdrive from a 69 GMC be a SM326? If so, is it the same as the one for Chevy?

Yes, 1966 and later overdrives were SM 326 w/sychro first. GMC and Chevy should interchange. What year are you planning to put the 1969 transmission in? The SM326 likely has a larger bearing retainer on the front and finer spline on the tail from earlier non synchro (pre 1966) transmissions.

The casting number on the tailshaft is R10Q and the side cover has seven bolts. The early ones were R10H with 4 bolts on the side cover and non synchro first.

Here is some free reading material:
http://speedprint.com/deves50/overdriveindex.php

Regards,
Steve
New Orleans