Quote:
Originally posted by LarryIII
Eddy,
<<<The AWD in a manual tranny has a sealed 3rd differential inside of the transmission. It is filled with it's own special fluid and has clutches in it like a LSD. So like a Limited Slip rear end, the more spin this 3rd diff sees, the more power gets transferred to the rear diff. >>>
I first ran accross this technology in the late 60's. It was used by FMC Corp. to transmit high starting torque to machinery from large electric motors. It was known as a "soft start coupling. The fluid is some kind of silicone based fluid that has some interesting properties. As the shear rate increases, the viscosity increases (it gets thicker). It essentially pours like milk at rest but turns into something like silly putty or road tar at high shear. I think it was developed by either Monsanto or 3M.
Larry III
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And now it's called a 'viscous coupling,' right? I think a lot of AWD setups out there use it now - including smaller SUVs like the CR-V.
Thanks for the history!
