The Hone Overdrive

[scott12180]

Could someone tell me the workings of the Hone aftermarket overdrive from the 60's and 70's?

Did these contain their own oil supply, or did they depend on circulation from the main transmission?

And were these effectively a gear splitter in that they could be engaged at any speed, even in reverse?  Or did you need to get up to a certain speed and then you could engage them? 

 

Thanks --- Luke

[Spinneyhill]

https://www.stangerssite.com/honeodrive.html

says this, inter alia,

"In the late 1960's, Fred Hone marketed and sold the Hone-O-Drive, an overdrive unit he had been developing for four years. Opening the  Hone Manufacturing Company in Santa Fe Springs, California, Fred designed and built this self-contained, fully lubricated, 2-speed synchromesh planetary transmission that is manually shifted from 1:1 Direct Drive to a 1.43:1 (or 1.47:1, depending on which article you read) Overdrive. This effectively changed a car with a 4.11 rear axle ratio into one with a 2.87 ratio. Engagement/disengagement is supposed to be available at any time with no neutral or freewheeling. You just ease off the throttle for a moment, to lighten the drivetrain load, and then move the shift lever."

 

The web site has these pictures (and others):

  Model 100 fitted to Ford 8" differential.

[alsancle]

10 years ago there was a Mustang for sale with one of these units installed.  I wish I remembered more of the details.

[Spinneyhill]

One trouble with these things is that they increase the "unsprung weight" in the car, i.e. they are added to the diff. and bounce up and down with the wheels etc., worsening ride. Another problem is they introduce an extra torque into the springs, pulling the axle down. When the axle bounces, they add further torque to the axle, twisting the springs. The springs are forced to act in a way for which they were not designed. Maybe that is OK, but ....