Transmission / Overdrive: Overdrive issues

[Joe Tondu]

1950 Champion

after removing the tranny to replace the clutch my overdrive is not kicking in. It was working when I started the repair.

Didnt do anything to the solenoid so not sure that is the problem. I do remember something about when you activate (I think) 3rd gear, it will move the overdrive lever at a certain point. I cannot get it to do this now and am thinking my problem lies somehow in the linkage operation. Any help would be greatly appreciated. Thanks.

[gordr]

1950 Champion

after removing the tranny to replace the clutch my overdrive is not kicking in. It was working when I started the repair.

Didnt do anything to the solenoid so not sure that is the problem. I do remember something about when you activate (I think) 3rd gear, it will move the overdrive lever at a certain point. I cannot get it to do this now and am thinking my problem lies somehow in the linkage operation. Any help would be greatly appreciated. Thanks.

Third gear has nothing to do with that. Reverse gear will internally lock out the overdrive because of a mechanical interlock within the transmission.

Number one cause of OD not working after transmission re & re? Improper adjustment of the lockout cable. If the lockout lever on the OD case is not fully back against its stop on the housing, overdrive will not engage. It's best to adjust the cable so that the lockout knob is about a quarter-inch clear of the bezel with the lockout lever fully against the stop.

[Joe Tondu]

Ok, I’ve tried readjusting the cable. A mechanic tested the solenoid and said it was bad. Don’t know why, it was working fine before. Replaced it though. Still not shifting into overdrive.

im still not clear about how the reverse gear activates/deactivates the overdrive.

something in this has changed though. It seems that manually operating the linkage at the tranny will not do anything to the overdrive linkage. I remember it did before I did all this. Could it be something with how the cable is attached to the fixed bracket? I’m obviously missing something here.

[gordr]

The internal overdrive linkage to reverse gear (and only reverse gear) cannot be seen from outside. There is a bump on the detent can for first/reverse gear, which hits the end of the overdrive shift rail, which protrudes slightly into the rear of the transmission main case. In reverse position, that bump pushes the OD shift rail back by about a quarter inch. The manual lockout lever does the same thing, by pulling on the rear end of the shift rail, by means of a semi-circular cam on the lockout lever shaft engaging a cutout on the shift rail. The lockout lever can move the shift rail, but the rail cannot move the lockout lever.

You can test this. Crawl under the car, and disconnect both the first/reverse shift rod, and the OD lockout cable. With the transmission rear lever in the neutral or low gear position, operate the manual lockout lever by hand. You will feel it engage the overdrive shift rail and move it, against strong spring tension. Now shift the transmission lever into reverse (all the way forward), and operate the lockout lever by hand. You should feel it to move freely, without any resistance at all, because the internal lockout has pushed the shift rail back.

Note that the correct adjustment of the lockout lever is that it be all the way back, resting on its stop, when the lockout handle is pushed in. Not close to the stop, ON it.

I doubt the solenoid is bad. They are pretty rugged. Could be the wires got put on the wrong screws. That would cause it to do nothing. Could also be a problem with the governor, or with the lockout switch on the back of the OD housing. Both are kind of vulnerable to being damaged when the transmission is being muscled into/out of the car.

Do you have a shop manual? There is an overdrive troubleshooting flow chart in there that can be really helpful.

[Joe Tondu]

Still can’t get OD to work

Replaced solenoid. Checked all the electrical. Seems fine. Fuse good.

Made sure lockout lever is solid on stop.

What could have happened inside I wonder? Drives fine but no OD

And it WAS working when I removed the trans to get to the clutch.

Mystery

[RadioRoy]

If you did not muck around inside the transmission when you replaced the clutch, and did not drop the transmission on the concrete, then the transmission internals are still good. Don't make more work for yourself by speculating and then taking things apart.

The 1950 Studebaker shop manual has a nice step-by-step guide to troubleshooting the electrical part of the overdrive. Try those steps. The overdrive is mysterious to many people, but it actually is a simple device.

The solution is likely to be much more simple than you think and easy to fix as long as you don't mess around with the parts that are still good and, by doing so, make them bad.

[Joe Tondu]

I’ve check everything. A mechanic checked all the electrical. Continuity good. Everything works on the lift, but no OD engages when driven. I didn’t touch anything internal. Could the OD SHIFTING mechanism somehow be stripped inside? Don’t know how that would be possible. Is it possible that the OD lever is not located right? 180 degrees off? Running out of ideas here. It’s got to be something very very simple I’ve overlooked.

[christophe]

Here is the troubleshooting chart from the 47-49 manual.
I hope this will help.
Nice evening to all.

[DieselJim]

Does the governor have a boot covering the wire? Could be unplugged. The lock out switch on the rear of the trans, use a meter to check with trans in neutral. I saw that was all checked. Check the governor. Remove it and operate it with a drill. Using a meter to check it is making a ground when it clicks.