- Home
- About Us
- Join/Renew
- Member Benefits
- Member Pages
- Log In
- Help
- Museum Store
Can someone explain installing the pin which enables reverse in free-wheeling?
Randy, is this for your ’31 or your ’35?
Bill
The ‘35 has the pin missing so I propose to rectify this…sooner or later.
I know that I had this apart when I removed the engine from my ’34. Here’s a photo of the linkages into the tranny, freewheel and power brake unit. I can’t remember the details.
Randy, By design, Free-Wheeling prevents the car from backing up. From the driver’s seat, take the engine as rotating in the POSITIVE direction. Transmission input and output shafts turn in the same direction in all forward gears. Without Free Wheeling, both transmission output shaft (T) and drive shaft (D) have the same positive rotational value (T = D). In reverse, the transmission input and output shafts turn opposite to each other.
During normal driving, the transmission shafts remain locked together, so the engine can hold back the speed of then car. However, during Free-Wheeling, an “over-running clutch” allows the drive shaft to turn faster then the transmission output shaft. This over-running clutch effectively de-coupling transmission output shaft and drive shaft (T < D). The transmission output and drive line are re-coupled when the engine increases the transmission shaft speed to match the drive shaft, allowing acceleration of the car. (T = D)
On the other hand, operating in reverse, the transmission output shaft rotates the opposite direction, providing negative rotation (-T). When the drive shaft stopped, it has zero rotation. (D = 0), which still a larger positive value than the transmission output’s negative rotational speed. [D > (-T)] Therefore, the transmission output shaft in reverse gear does turn, but that over-running clutch will not allow the car to back up.
I expect the function of the pin is to lock out the Free-Wheeling feature, locking the rotation of the transmission output shaft to the drive shaft and allowing negative rotational values for both transmission and drive shaft. Without a definite lock-out feature, Free-Wheeling may cause severe ‘white knuckle syndrome’ when going down steep hills. Herb
Hi, Herb. I understand the workings of free wheeling; what I need is the details of how to dismantle the transmission and install the locking pin which was likely left out of my car’s transmission during previous work.
I drove the ‘35 some in fw at Kalamazoo. It works fine on the open road when there is plenty of momentum to allow time to complete the shifts; best to lock it out around town though.
regards,
RR