The Stovebolt Site Forums The Shop Area Driveline What years were Torque tube transmissions used

I need a new 2nd gear synchro in my 1950 3 speed. I have a local guy who said he had a 1953 3 speed. I went to check it out and it is an open driveshaft Transmision. Would the synchros from the open drive shaft tranny fit my tranny? How late was the torque tube used too? Also who sells synchros for the 3 speed and around what do they cost.?

The enclosed driveshaft (torque-tube) was used through 1954 in Chevrolet (and, GMC) light trucks.

A 1950 model used a two lug synchro. 1953 and 1954 used a 4 lug synchro. 1955 and later was different again and will not work in the earlier cases. However, two of the lugs can be ground off and make it work in a 1952 and earlier. It has been a long time since anyone sold these. Occasionally they appear on eBay and sell in the $300 to $400 range. The brass synchronizer rings were available to rebuild the synchronizers at on time, but I think that has been a long time. Passenger cars used the same synchronizer. I would watch eBay or tear a bunch of old 3 speeds apart and maybe you will find a good one.

Thanks for the reply. I have attached a picture of the non torque tube tranny I am talking about. Correct me if I’m wrong the does the casting date F 1 64 mean it was cast on June 1 1964?

You didn't give us a good view of the transmission, but I think that is a 1955-57 Chevy passenger car transmission. All the ones I ever saw looked just about like that (although the cast numbers could be different depending on a few factors). Good luck with it. Not by any stretch of the imagination my favorite 3 speed, but some consider it okay. Not sure who has synchro rings for them today. I'd call Wade Transmission & Gear in Dallas. 214-747-4868. They'd know if anyone would.

Try Kanters.

Chevs of the 40s advertises the brass synchro rings for passenger vehicle transmissions, aren’t they the same for the truck 3speed?

Yes they are the same, I have seen the rings also, But-----
If you look closely at the outside of the syncro "drum" assembly, the brass ring has been staked from the inside of the ring and protrudes slightly into the holes in the outer drum area. This is what holds them in the syncro assembly. This was a factory press operation that would be difficult to duplicate without some specialized tooling. I don't know of any shops in this area that still
rebuild these units. Probably the best you can do is find a good used one.

Other than possibly the bearings, nothing from that 64 transmission can be used in the earlier series.

Fred

The brass synchro rings have been available off and on. I didn't realize they were being offered again. I guess the complete synchro has become expensive enough to justify rebuilding them. We used to heat the synchro and freeze the ring and press them in with an arbor press.
The rings are the same on passenger cars as trucks and both torque tube and open drive shafts.

Please find somebody who owns a Hollander manual and look up that transmission. You won't be able to do much of anything until you know what you have. Or call Wade's in Dallas and ask them.

Found on an Internet search: "67 C10 1/2 ton with a 250 L6 and a three speed GM transmission with the numbers 3880210 on the drivers side"

There was no indication about this transmission being original to the vehicle.

Best I've found is:

IDENTIFICATION - common light duty Muncie 318 Cast iron case and extension housing with 4-bolt side cover. Has non-synchro 1st and a "barrel" type 2/3 assembly. Units from 1940-54 have enclosed driveline. Those from 1955-68 may have electric overdrive (designated as 319). May have short or longer extension housing. Some of 1964-65 units have larger gears with the same tooth count as the 1940-68 units. 1st gear ratio Suffix A equals 3.03:1, Suffix B equals 2.42:1.

Synchro replacement parts not available at this time.

Here is what Hollander cites. 1955 through 1968 early can be interchanged as a unit, but you will have to have an open drive shaft. It cites the GM as well as Borg Warner part numbers for the main drive gear as well as the cluster gear. None of the internal parts will work in your closed drive shaft transmission.

https://photos.app.goo.gl/iQsnfNF4ZnpeKfyDA

You are probably correct that it was produced in 1964 which means that you have the later main drive gear which is irrelevant because none of this will fit into your case.

rfs56trk We used to drill thru that staked in brass ring and put an 8 penny nail in there for a rivet so the ring would stay in the hub. That worked very well. This was before we could afford Muncie 4-speeds.

I have obtained the following information based on research and working on these transmissions for many years.

Unfortunately the SM318 designation was used for the the torque tube transmissions as well as the open driveline units.
This is confusing because there were several variations over several years, some are noted above.

None of the gears and syncros from the open driveline transmissions can be used in the torque tube version.

55-57 cars used the long tail housing open driveline transmission. Also used in trucks from 55 through some 63's.
Corvette used the long tail housing but had a different gear set with a rear mount and a shifter mount.

58-65 cars used the short tail shaft version with a rear mount.
There was another gear set offered in 58 for cars with a 348 engine, it was also available in Pontiac's and later Corvette's.
It had a 2.47 first gear and a 1.53 second vs 2.94 and 1.68 in the standard version.

Trucks used the short tail shaft version from 63 through 67 with the standard gear set.

Overdrives (SM319) came with the standard gear set from 55-63.
64-65 overdrives and regular transmissions used gears, shafts and syncro units with a different pitch.
This version was also used in cars, Nova's, and Chevelle's. None of these components interchanged with the
earlier versions.

The Saganaw 3 speed full syncro w/overdrive (SM326) was available in 1966-69 in cars and trucks.

Fred

rfs56trk We used to drill thru that staked brass ring and put an 8 penny nail in there for a rivet to keep those from coming out during agressive shifting !! Peen it grind smooth,poor boy method before we could afford 4-speeds.

rfs56trk We had that special tooling,you do too,drill thru that pucker make a rivet out of an 8 penny nail,grind smooth,synchronizer stay in a lot better during agressive shifting,(speed shifting) !!!