[The Watcher]

The torque tube is the tube in which the drive shaft runs to the rear differential. In most vehicles, like a hotchkiss drive, the engine twists against the frame or body to spin the drive shaft. The drive shaft then attempts to turn the differential. This means that engine torque tends to lift the right tire and push down on the left tire. It is why a car with an open differential always spins the right (passenger side) tire on takeoff, since engine torque is twisting the whole axle assembly.

The torque tube instead, mounts directly to the differential and to the transmission, so that no twiting force is applied to the axle or the frame by the engine. Instead, the engine twists the shaft inside the torque tube, which then transfers the torque right back to the transmission case. The rear axle, then, does not attempt to twist against the body under power.

You could change your car over to a Hotchkiss drive, where the engine torque is transferred to the body, and the rear axle reacts to engine torque by attempting to turn, causing weight distribution change side to side. But you’ll need different engine mounting, different springing, change to a 4 link style suspension in the back, and other changes, as well. I would NOT suggest doing that. Instead, if all else fails, a very good machine shop should be able to repair or fabricate a new torque tube. Likely yours is damaged by hitting something, or a failed drive shaft or joints hitting it.

It is complex, heavy, and expensive, but it was done to spare your car from twisting the frame or body from engine torque, and to improve cornering characteristics and prevent “under power” handling changes.

[VOA]

“
I am ordering parts to repair the torque tube on my 1970 Opel GT.
“

Sorry I can’t give you specific info.
BUT...back in the day when I had a 1973 Opel GT, Buick was the dealer
that had sold the Opels and had spare parts.
Maybe you could check a Buick dealership and get a lead on the parts
or perhaps a retired Buick parts manager that could help you out.

Good luck with every thing.
I loved the Opel GT, but still remember one gawd-awful blistering hot
summer week when I had to mend/replace the wiring harness.
Definitely an exercise in sweat.

[JRios1968]

[hwkbeer]

“My torque tube needs help. Why should I do it?”
It keeps the neuter valve and the flux capacitor aligned.If you get turbulence between those two components your car will be immediately sucked into a black hole

[Allegra]

My torque tube needs help.

Yeah, I hate it when that happens.

My flip zorch needed help recently.

It got better, though.