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View Full Version : ?Torque Tubes conclept


coachgeo
06-02-2002, 06:01 PM
This is the main suspension/drivetrain difference between Mogs and domestic vehicles. Could someone explain how the torque tube system works? I ask because cruise speed in a 404 unimog is around 45 to 55, slower up hill. The logical idea is to use an aftermarket overdrive for hwy use and they do make them for torqe tube vehicles.... but not the Unimog go figure. Maybe an adapter could be made to convert to torque tube specs that will allow a different torqe tubed vehicle's overdrive unit to fit. Now be aware.. the Unimog Tranny is said to overheat at sustained speeds used on American roads and the axles as well!!!

unissamog
06-03-2002, 09:04 AM
The torque tube concept:

The tubes allow for a relatively simple (and yet complex) suspension.

The only attachment points are the torque tube and the panhard bar.

http://www.west-4x4.demon.co.uk/flexsusp.gif

The torque tube has the driveshaft contained within it. It is hard mounted to the axle, and has a flexible coupling to the tranny/t-case. The tranny has a MASSIVE set of mounts to the frame.

The side to side is from the panhard rod.

This system allows for LOTS of flex, without tons of linkages. One odf the coolest pionts about a unimog is the frame flex that mercedes added in to the system, so that the frame assists with the overall flex.

Unfortunately adapting the torque tubes to another vehicle would be insanely complex......so you are better off to stick with a mog, or just get the axles.....unless you go hybrid!

Cruise speed issues:

There are many factors that contribute to the cruise speed....The tranny is on weak link, but it is the axles themselves that do a lot of the limiting in the speed. The 7.56:1 gear reduction causes massive RPM issues. Say you are going 55mph with 'mog axles.....that means that your 37" tires are turning ~500 RPM, which leads to 3779RPM at the pinion.

Basicall it all boils down to oiling, and the lack of circulation , and effective cooling of the oil. This is easier to resolve in the tranny than on the axles.

Unimogs were ORIGINALLY designed as a tractor, that coud goto town with the weeks harvest. And the 404's were designed as a vehicle that would only ever see the speed of a military convoy, so the axles were never designed to haul ass for long periods of time.

There are "high speed"axles that were used in 406 fire trucks I believe, but you will pay $$$$$$$$ for them, as they are rarer.

Basically, my theory is, If I am going to throw unimog axles on my rig (or the whole chassis in my case) it is going to be a wheeling rig, not a daily driver, so I can deal with the speed limitations.