[Fot] Big TR OD and Gearbox rebuilding

Randall TR3driver at ca.rr.com
Sun Mar 9 13:30:33 MDT 2014


> Not quite the same subject : it's very unhealthy to an A-type 
> to reverse the
> car with the overdrive engaged for some unorthodox reason. 
> Can you wreck a
> J-type overdrive in the same circumstances?

The reason is the one-way roller clutch in the tail housing.  It forces the output shaft to turn no slower than the input shaft,
when turning in the forward direction; allowing it to carry the torque while the main clutch is moving between direct drive and
overdrive.

But when rotation is the other way, the clutch forces the output shaft to turn no faster than the input shaft.  With the overdrive
engaged, it still forces the output shaft to turn faster.  Something's gotta give ... Usually the roller clutch explodes and takes
the housing with it.

Yes, J-type has the same problem.  Normally, the lockout switches prevent engaging OD in reverse, but that won't help in the case
Tony mentioned.

Randall



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