The Stovebolt Site Forums The Shop Area Engine Shop How does the overdrive work in my '55 2nd series?

I've got a '55 Chevy 2nd series and I'm not sure how the overdrive should work. (Parts may be missing). Is there a manual that covers all this information real well? I've been told you have to push in the clutch and pull a knob on the dash. The knob and cable are gone, but I can see where it would attach on the trans. Also, there are things on both sides that look to have had wires going to them. The one on the driver's side looks like a solenoid of some sort. What is that for? There is also something on the right side with wires. Any help would be greatly appreciated. The wiring is mostly missing so I don't know where they should go or anything.

Welcome. Assuming that this is a Muncie or Sag Borg/Warner unit...the information you seek is archived here: Deve\'s Overdrive web page Additionally you may want to Google up the "Old Burb Club" for home brew wiring.

Find a MoToR's or Chilton's manual that covers 1950's cars...that will have a section on OD trannies...the operation is pretty-much standard on all 1950 & later US OD set-ups, which is almost always a Borg-Warner R-10 unit.

The cable & knob you describe is the "Lock-out cable": this is used to manually disable the OD function. Usually, when the knob is pushed-in, the OD is "enabled"; when pulled-out, the OD is "locked-out".

There is also a governor on the OD section of the tranny, as well as a solenoid which engages/disengages the OD (causes up-shift/down-shift). There is a relay under the hood, which links the solenoid & governor to the kickdown control on the throttle linkage, and also the ignition.

If any parts and/or wiring is missing, the OD won't function.

If you get a reprint of the factory shop manual for your truck (Check American Classic or one of the other "specialists"), this should have service info on your OD.


Good luck !

Thanks guys. Now, is it worth rebuilding this trans? Are there parts availble like the solenoid and governor if they are worn out? It sounds like it would be really kind of neat if it all was working. I'm assuming that I can leave the stock rear in it and cruise on the hightway just fine then...right?

Everything is available. Either on Ebay or from a salvage yard.

I have a 55 2nd with the 235 and purchased the OD transmission. I only got the transmission.

I wanted to stay original so I searched and found all the other parts.

At present the solinoid, governor, and the kickdown switch are listed on Ebay. The relay switch and the disengaging cable show up periodically.

You can purchase the wiring harness from some of the popular venders.

The hard parts to find are the bracket for the kickdown switch and the accellorator linkage with the paddle - for the kickdown switch. You can find these with a lot of searching or construct your own.

There are other ways to rig the OD transmission to make it work. Search this site and the internet and you will find them.

Best of luck.