Overdrive Interlock Plunger

Decided to gather all the transmission parts for the 48 overdrive, and was doing pretty good until I got to the little bullet shaped plunger. I think its supposed to keep the OD from engaging in reverse, not that you could rev the engine to 22 MPH in reverse.

Question is, Where do you put it? The later model BW OD trans don't use it.

Thanks

Abe

Abe, The interlock plunger slides into a bore between the slot for the pawl and the bore for the shift rail. The plunger will then contact the "V" slot on the pawl. The pawl needs to be rotated from what you have in the pic. What happens is when the shift rail is in the "lock out" position (manual lockout or reverse) the plunger is forced down into the "V" and will not allow the solenoid to engage the pawl for overdrive. When the shift rail is in the Overdrive (control knob in) position the plunger will then be pushed up as the solenoid engaged the pawl for overdrive operation.

Dee:

You are right as usual. I discovered the passage in the OD adapter housing, you have to insert the plunger from the shift rail area with the shift rail assembly not installed. The short shaft of the shift rail assembly has a small diameter section where the plunger resides, and then moves the plunger as the shift rail is moved toward the rear lock out position and the plunger makes contact with the larger diameter section of the rail shaft.

Pretty cleaver of those Borg Warner engineers. I have diagrams for the later model transmissions that lack this feature. Don't know what I would do without the help of folks on this forum.

Thanks

Abe

Nice job Mr Peecher!! did you ever get you engine back in..on the road??

Jeff, if you're referring to the pic of the "over the side" R&R...yes, it's in. The car has been restored and is back on the road and that big engine really moves it!

Boy oh boy, very nice...How fast do you drive before you engage the od?? These little v-12s git it when running properly , and rpms are up..

Do you have a 4 barrel on yours??

The OD gets engaged immediately...the 332 cubic inches, mild cam and 4 barrel (Carter AFB) makes this rig a whole different breed of cat.

I'm considering an upgrade to a Borg Warner for my '41, which was built without one. Is there anything different about the transmissions used with these overdrives?

Dave, while the "guts" of the 3 speed transmission are the same for either standard or Overdrive, the transmission case is different at the rear to accommodate the adaptor plate for the OD unit. The side cover for the transmission may also be different to accommodate the "shift rail" for the OD unit. You'll need to get a complete transmission with OD even if you swap transmission innards. The OD adds 13" to the length so a shorted drive shaft and torque tube are needed from a OD equipped car. I believe the cross member on the '41 will allow the use of the rear engine mount designed for the OD.