Overdrive

You're probably confusing this company with Ahlberg Bearing.
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Doubtless...

Nice score on picking out "one of those" that existed for likely a short time - but left SOMETHING of utility.

You search "overdrive Model A" and you get Mitchell, Ruckstell, Warford, Columbia, and all the names we've all seen and drooled over. It gets harder trying to dig out the less known.

Period correct - but still a downgrade in judging? Depends of what exactly you judge.

I find this modification INFINITELY more interesting than a restored to production line car.

Not that I don't admire high levels of handwork and attention too.

Joe K
 
I would judge this thing to be one of the niftiest Model A period accessory things ever.I would probably find it's defects,most likely bearings,seals,shims,shifter detents,etc. and replace them.99.9% of Model A guys today would never run that unit hard enough to do it any harm.Kids won't be out in it thrashing the gears like they would have back in the 30's.If I had that rear end in my shop I would go out in the yard and gather up enough parts to build a car over it.
 
It may very well become available if you are interested. I do not have the equipment or expertise to tackle fixing it. Will probably replace it on my car.
 
Just to be clear, are you 100% certain it's an overdrive and not a free-wheeler? Lots of free-wheelers also mounted in that location.
 
I don’t know what a free wheeler is. This one has a shifter like a Mitchell, and two different speeds in each gear like a Mitchell.
 
Free wheeling amounts to a "drive with a ratchet" which as long as the engine powers it, it moves the car forward. If you let off on the gas then the drive "disconnects" from the wheels.

Which some say - isn't that what every standard gearshift car is now?

Not really. A large part of standard shift driving involves the clutch, or more accurately "interaction" with the clutch.

A free-wheel removes the clutch from the game entirely.

A free-wheel has to be "switchable" - to allow restoration to typical standard transmission drive - or to enable true "free wheeling" for reasons of fuel economy. Hence the likelihood of a lever or button to allow driver selection.

Having the car in "free wheel" mode tends to wear out the brakes prematurely.

Joe K
 
It would be interesting to know if that unit is just a simple gear drive set up or if it's a planetary gear drive set up. The size of the case is large enough that it could be either one. Most freewheel clutches used rollers with ramp plates back then, This is what the Borg Warner R10 & R11 electric ODs used.

A lot of seals back then were leather like the Chicago Rawhide types. While they last a long time, they do eventually wear out. Some were nothing more than felt. There could have been a reason for the rarity of a unit like that. It could have had problematic reliability issues for a number of reasons. Lot's of questions on that unit that would need answers to know how good it was.
 
The over running clutch,or free wheeling came into use in overdrives when they started shifting them with an electric switch and a governor.At a certain speed you let off the gas,and the unit would shift up.If the trans and OD unit were still solidly connected at road speed they may never shift.The free wheeling lets off the strain on the gears so they will shift.When the OD is in the free wheeling is not in play.The pressure is still on the gears though,so to downshift out of OD you stomp on the gas,and a switch will momentarily kill the power to the coil,relieving the pressure on the gears to let the solenoid to shift it down.Free wheeling not needed on a manual shift OD,you throw the clutch to relieve the pressure to shift.
 
Hey folks, I learned what I was l needed to from all of your replies. Basically, no one knows anything about this equipment. That’s enough for me, I am getting rid of it. Thanks, Jeff
 
jlking2010 said:
Hey folks, I learned what I was l needed to from all of your replies. Basically, no one knows anything about this equipment. That’s enough for me, I am getting rid of it. Thanks, Jeff
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Please don't get RID of it, rid of it. Someone may want it for the vintage history of it. Sounds like a rare piece.
 
I should have said, I will remove it from my car and replace it with stock torque tube and drive shaft. I won’t throw it in the scrap pile!
 
If it works, I would re-route the vent and see if it stops leaking, see Post#19. The way it currently is, it is building up pressure insise and pushing oil out the easiest place.
 
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