The Stovebolt Site Forums The Shop Area Engine Shop Open driveline/torque tube

Hi,

I have a 41 3/4 ton. I would like someone to explain the difference between an open driveline and torque tube. Much appreciated!

Jeff

The torque tube driveline was completely closed from transmission to the rear end with the driveshaft running inside it. The torque tube itself was used to primarily position the differential and locate it securely. The rear springs did not locate the rear end as is the case on an open or Hotchkiss style differential. The U-joints are exposed on an open style and the driveshaft is very visable as opposed to being entirely unseen in the torque tube rears. All that is built now are the open style. This started on the trucks we concern ourselves with here on the 54 model year. Many of us are still of the opinion that a proper torque tube is still a decent idea albeit one that requires more time and trouble to repair. It pulls the rear end along and allows the springs to provide suspension action only while providing a solid base for the springs to rest on thus eliminating the up/down movement of the differential. It is very limited in the available gear ratios however, 4:10 being stock on the half tons with only a 3:55 as a replacement option. This and the popularity of 5 sp OD transmissions (and others) which require the open driveshaft are the reasons folks change them out. I'm sticking with the General's rear and have no real desire to drive 75 MPH in a 55' Y/O truck. Besides, at 55 my old inliner really sounds great!

Here is some more information on tourque tubes - it adds very little to 53moneypit's information.

The torque-tube was used on 1/2 ton Chevrolet and GMC trucks through the 1954 model year. I heard that it is still used on C4 & C5 Corvettes and modern Aston Martins (I could be wrong on this).

Tim

http://en.wikipedia.org/wiki/Torque_tube

I don't know anything about Aston Martins except they are fast and expensive and last I heard Prince Charles had one.

C4 Corvettes used a torque arm between the transmission and the differential. A C4 still has a normal driveshaft with u-joints. The torque arm may serve a similar purpose, but it looks a bit different.

C5 and C6 Corvettes are a bit more different. The motor is in the front like most cars, but the transmission and differential are both at the rear. They do have a tube with a shaft inside it between the front and rear and I presume it is called a torque tube.