The Stovebolt Site Forums The Shop Area Engine Shop How does a Torque Tube Work?

A friend came over and looked at my 53 the other day and was baffled by the torque tube. He asked how it worked, that was when I realized that I didn't even know how. So how does it work? Is it just an enclosed driveshaft covered in oil? Thanks!

just a drive shaft inside a tube oil can transfer from tranny to rear end i think.any that i have pulled apart have gear oil inside the tube.

Thanks V6 Jimmy! I kind of had the right idea(yeah whatever :rolleyes: ), just needed some back up. Thanks

The torque tube arrangement also employs only one u-joint which is in the rear of the transmission. At the axle end the spring holders have a pivot pin in them so the axle can rotate backward and forward. If you ever take out the transmission and put a jack under the torque tube you can see the wheels moving in the wheel well. I also believe that is why the wheels are not centered in the wells. In the torque tube there are bushings and a seal, the latter keeps transmission oil from going down the tube to the differential. If that seal goes you will never keep oil in the trans as it will overflow into the diff and either blow out the vent or axle seals. Been there done that.

Olblu, you are very very smart or you have had to many problems that you had to fix. Thanks for the reply, much appriciated.

Let's go with the "too many problems" theory! Although many people swear by the TT I do not like the complexity of it. The seal in the tube went and I put in one of those Okie seal/bushing parts. It went in well but one of the things they mention is to make certain there are no burrs on the splines or n the area which might cause the seal to tear and leak. I have been driving mine with the fix for a few miles but because of my paranoia I still crawl under the truck after each trip and check the trans fliud! Crazy or what! I have a Plan B in case it does fail and at present am rebuilding a 1957 three-speed transmission and a 1957 differential to replace the torque tube system. They are open drive.
Bill

The reason for the torque tube is that early manufacturers wanted the driving force to be transferred to the center of the vehicle. On open driveline models, the thrust to push the car/truck down the road is transmitted to the frame by the rear springs. With a TT, it goes to the back of the transmission housing and from there to the frame at the rear motor mount. Ford cars used torque tube drive from the Model T to 1948, and Chevy cars and trucks changed to open drivelines in the early 50's. American Motors (Rambler) used a torque tube until the mid-1960's. There are pros and cons to both systems, so "ya pays yer money and ya takes yer choice!"

Since the u-joint is enclosed it runs in oil and is protected from the elements and road debris. When it is properly maintained, u-joint failure in a torque tube system is unheard of, unlike the Hotchkiss drive (open driveline).

Agree with fab51 about the u-joint. In my opinion the u-joint in the TT set up ia weak point. The four 1/4" bolts that hold the joint together take a lot of punishment. The ball housing has to be set up just right so that there is no excessive play which would cause the u-joint to hit the housing (you will see heavy scoring) or if it is too tight the u-joint will not flex and could break. In the manual there is no specific specification for determining too tight or too loose. It is a matter of feel. Nevertheless as hot rod lincoln rightfully says, there are pros and cons to both!

Thats interesting. thanks.

Rear axle rotational torque is what the 'torque' in torque tube is all about. The forward thrust of the axle housing is transfered to the frame through the springs as in any rear drive car since the tube is free to slide fore and aft at the front end. The big advantage is the dampening of the torque attempting to raise the front of the axle housing on acceleration. The long torque tube provides excellent leverage to control this. An open driveline vehicle suffers from spring wrap and resulting axle hop due to this unless some sort of control in used, bars or pinion snubber.

Of course the ujoints in stovebolt torque tubes are too small to take a lot of punishment from big motors. But, I have seen a lot of pickups with v8s and stock drivelines in years past. The v8 clutch housing will bolt up to the pickup transmission but you have to be creative with motor mounts.

I think Buick was the only major brand to use torque tubes with fairly large V8s, in the mid to late 50s and they worked really well.

Did you ever do the '57 3 speed & open driveline swap? Thanks.

You guys are awesome. Thanks for the tutorial. I have to pull my 4 spd and need to know how.

Be sure to put your jack stands under the frame, NOT the axle housing. Spring tension on the torque tube can cause it to slam down pretty violently if you unbolt everything at the back of the transmission with the weight on the springs!
Jerry

I did it. It's out. You weren't kidding. That suckers heavy. I rigged up a sling over the top Of the cab. I strapped the trans and cinched it up after dropping the crossmember and getting the TT out of the way. I pulled the bolts and slid it back. I ratcheted it down on a dolly, laid it over and pulled it out. I was very pleased with myself. Next is the hood removal and then the engine. I'll be very relieved to have it out and on the stand.
I plan to pull the top off the tranny just to see if the gears are showing wear. Then button it up and clean the outside.
I was surprised to see there were no needle bearings and no caps on the u-joint. Must self lube from the trans oil.

The pinion gear when pushing against the ring gear which turns the axles then the wheels meets with resistance.

So as the pinion gear turns against the ring gear (and rear diff assembly, axles, wheels) the resistance of those parts to move causes the pinion gear to want to ride up the ring gear in the opposite direction that it is trying to turn the ring gear.

Being the pinion gear is fixed to the rear diff/axle housing assembly it is not free to rotate in the opposite direction/climb the ring gear. So that reverse force will cause the whole rear diff/axle assembly to rotate and twist.

The Torque Tube's job is to provide rigid support to prevent the rear end from twisting when engine torque is applied to the rear end.

Rear leaf springs aided in controlling the twisting of rear end.

Rear coil springs without the torque tube requires the use of the 4 control arms to control the twisting motion.

There were some modern/late model autos that had an open drive shaft with a steel beam that bolted from the trans to the rear housing to act as a torque tube. Jeffrey

There were/are some modern cars (Corvettes &/or Mercedes) that had/have torque-tubes (in the last 10 years).

Torque tubes on Corvettes started in 1997 with the debut of the C5 generation. It's kind of a different animal than our trucks in that it has no u-joint and transfers power from the crankshaft to a rear mounted transmission by means of flanges with a rubber dampener. Benefits are no bellhousing adding lots of footwell room as well as nearly 50/50 weight distribution for awesome cornering.

LOL, I learned that the hard way when replacing the tranny on a 54 Chevy station wagon back in college. Needed a trip to the health clinic for a couple of stitches, then back to finish the job. I have a reminder above my right eye that's still visible.
Put a jack stand under the torque tube also, or at least a strap to restrain it before disconnecting the u-joint.

The Corvette torque tube serves a different purpose than on an AD truck. Basically keeps the body from twisting. If it weren't there, the body and frame would be all that's resisting the torque of the driveshaft between the engine and rear mounted tranny. The AD torque tube is loaded in bending, not twisting like the Vette example.