The Amazing Nash Healey Hudson & AMC Rambler Torque Tube Drive
Transmission leak? You need a good torque tube stabilizer trunnion for a safe, straight, reliable drive.
An old, worn or bad stabilizer trunnion will fail and disable your vehicle!
In a torque tube drive car, power is directly transmitted from the rear wheels through the covered drive shaft, (torque tube), through the transmission body and engine assembly through the torque tube trunnion. An old or defective trunnion will cause the rear wheels to steer the car. They will move front to back and left to right under the coil springs, because the torque tube flexes at the trunion. The body simply rests on the rear coil springs, and will start to bobble. The car becomes unstable and control varies from poor to very difficult. Instead of being safe and rigid, the drive line behaves like a rubber band.
To make it easier to understand, take a conventional rear wheel drive car with an open drive shaft, and remove the rear leaf springs and try to drive it. You can’t. The forward thrust power, or torque, needs to push through the rear leaf springs in order to move the car forward or backward. Now do the same with a closed torque tube driveshaft. The car will still move forward and backward because the power is transmitted through the torque tube to the transmission and the engine block, to which it is attached to, and pulls the car body from the front motor mounts.
''Torque tube'' is actually a closed covered drive tube surrounding the driveshaft, transmitting thrust through the torque tube drive stabilizer, to the transmission body, and through the engine block and transmission mounts, rather than through leaf springs or control arms in the rear. The turning drive shaft only delivers power to the rear wheels inside the tube.
The connection of the torque tube to the transmission is made through the Torque Tube Trunnion Stabilizer, in the housing at the transmission. Your original stabilizer trunnion will go bad because of oil leaks, heat, age, which cause it to soften or crack. Simply by disconnecting the torque tube for transmission service or u-joint replacement can break the old one apart. The rear axle differential and torque tube are a single rigid unit connected at the transmission through the the trunnion stabilizer. A bad stabilizer trunnion always causes unsafe driving because the torque tube flexes at the trunnion causing the rear wheels to steer the car. A bad or old trunnion will cause unstable or crooked driving.
Today, the Lexus LF-A, C5 & C6 Corvette, Mazda Miata MX5 and Porsche 928 and 944 use the torque tube. Buick used it in the '30's and 'mid '50's. Many cars and trucks used it through the years, including the Peugeot and Volvo 300 series. It is used in Nash Ambassador 49-57, Nash Healey 51-54, Hudson Hornet 55-57, some Nash & Hudson Ramblers through the '50's & ‘60’s & AMC through the '60's.
Nash Motors never made replacements. Scroll down to order one from NashRamblerRubber.com. Replacing the original for safe driving or at least carrying a SPARE is recommended. A new stabilizer replacement is not available on the road or from any of the usual auto parts or transmission sources. A bad trunnion will disable the vehicle. It will fail gradually or pop out under stress.
This Information comes from Wikipedia, service manuals, Google, and NashRamblerRubber.com
IMPORTANT: The trunnion is a stabilizer for the entire drive line. If fluid is leaking from the trunnion, the stabilizer is now soft and dissolving, and needs to be replaced because it will not function correctly. (see pictures) The leaking fluid is from the transmission or the rear differential. It collects inside the torque tube and slowly leaks out at the trunnion.
The rear differential and torque tube are one rigid unit. They are connected to the transmission through the stabilizer trunnion. This entire unit will flex at the stabilizer trunnion. The rear wheels, just under the coil springs, will then skew sideways, bobble, or move forward and backward steering the car causing it to become unstable or unsafe. Leakage coming out here will always cause the old stabilizer to become soft and not work correctly.
The old trunnion hasn't been replaced since the car was new, 60+ years ago. Nash never made replacements. New ones are oil resistant and designed for heavy duty non-racing driving conditions. You can address any leakage with one or two ounces of Blue Devil per quart of standard transmission fluid or differential fluid. Available at Napa or O'Reilly. Not for automatic. This may work. We recommend seal replacement. When you do this, the trunnion stabilizer will have to be replaced also since it may come apart upon dis-assembly.
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Give it to your mechanic. Enjoy safe straight driving!
Order a spare Stabilizer for replacement. Prevent long term breakdown