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Joe Tondu
02-04-2017, 11:33 PM
My '50 Champion has an overdrive. It seems to function except it has a curious habit that baffles me. With the overdrive engaged running say 40 mph in 3rd, and I downshift to 2nd, there is no engine braking as I would expect. It's like it goes into neutral. When I do the same operation with the overdrive disengaged it all works like it should. What am I doing wrong or what am I not understanding about this system? Does it not sound like I might need some adjustment? Doesn't make any fearful transmission noises. Enlightenment?

bezhawk
02-05-2017, 09:05 AM
That is correct in it's function. The engine free wheels when overdrive is engaged. There is a one way roller sprag inside the overdrive. Conventional gear (when you lock it out with the cable) locks the sprag, and you regain engine braking.

SN-60
02-05-2017, 09:11 AM
[QUOTE=bezhawk;1037078]That is correct in it's function. The engine free wheels when overdrive is engaged. There is a one way roller sprag inside the overdrive. Conventional gear (when you lock it out with the cable) locks the sprag, and you regain engine braking.[/QUOTE

That's not correct Brad,...once the overdrive engages, the drive line is 'locked up'.... and the freewheeling is eliminated until road speed drops below 15 mph or so, where the o/d disengages.

Sounds to me like an internal transmission problem. :(

DEEPNHOCK
02-05-2017, 09:28 AM
Some good reading....

http://forum.studebakerdriversclub.com/showthread.php?22236-Overdrive-Freewheeling

http://forum.studebakerdriversclub.com/showthread.php?35296-overdrive-free-wheeling

http://forum.studebakerdriversclub.com/showthread.php?87464-1950-land-cruiser-overdrive-freewheeling

http://forum.studebakerdriversclub.com/showthread.php?34151-overdrive

http://forum.studebakerdriversclub.com/showthread.php?57927-quot-Free-Wheeling-quot-Mechanism

http://forum.studebakerdriversclub.com/tags.php?tag=overdrive

http://www.studebaker-info.org/text3/OD.txt

http://www.oldcarmanualproject.com/manuals/trans/Borg-Warner%20Overdrive/index.htm




My '50 Champion has an overdrive. It seems to function except it has a curious habit that baffles me. With the overdrive engaged running say 40 mph in 3rd, and I downshift to 2nd, there is no engine braking as I would expect. It's like it goes into neutral. When I do the same operation with the overdrive disengaged it all works like it should. What am I doing wrong or what am I not understanding about this system? Does it not sound like I might need some adjustment? Doesn't make any fearful transmission noises. Enlightenment?

Hawkowner
02-05-2017, 09:28 AM
Your governor may be disengaging the over drive do you have engine braking in high gear and over drive.Rig a test light to the power wire on the solonid and watch.
Hawkowner.A

JoeHall
02-05-2017, 10:42 AM
Wow Brad, you surprise me with your answer. That is INCORRECT, if it freewheels all the time in OD. Sounds like the OD is not engaging. As others have mentioned, once engaged, engine breaking works just like in conventional drive. HOWEVER, once the car slows to a point that the governor disengages and breaks the electrical circuit, then it, "freewheels" as the OP has described. If it is freewheels all the time, there's a 99 percent probability the OD is not engaging.

SN-60
02-05-2017, 10:55 AM
Wow Brad, you surprise me with your answer. That is INCORRECT, if it freewheels all the time in OD. Sounds like the OD is not engaging. As others have mentioned, once engaged, engine breaking works just like in conventional drive. HOWEVER, once the car slows to a point that the governor disengages and breaks the electrical circuit, then it, "freewheels" as the OP has described. If it is freewheels all the time, there's a 99 percent probability the OD is not engaging.

The thing is Joe, the owner says the o/d IS engaging! :ohmy:

bezhawk
02-05-2017, 11:15 AM
Sorry guys, brain fart, you are correct. It will free wheel until the OD engages. IF you have the cable engaged.
When you down shift to 2nd, are you stepping hard on the accellerator, and kicking down? that will put it back out of OD and it ill free wheel then until the od re engages. It sounds like it is not re engaging due to most likely the governor. If you pull the cover off the governor, you will most likely find oil soaked points due to internal leakage. Also the points go bad, and the springs can get sludged.
Also check for frayed wiring.

JoeHall
02-05-2017, 11:57 AM
When upshifting, to engage 2nd gear OD, it always takes more RPM than it does in 3rd. However, once engaged in 2nd or 3rd, the OD should stay engaged whether upshifting to 3rd, or downshifting to 2nd. Unless, "kickdown" is used with the accelerator pedal, it should stay engaged till slowed back down enough that the governor breaks the circuit. If the car is dropping out of OD when he downshifts to 2nd, as Brad said, I'd suspect the governor is disengaging too soon. The good news is, they can be adjusted to engage earlier or later, and to stay engaged longer or shorter. Some governors have different pinions available, but I just play with the springs and points to get it where I want it. Its a real sensitive operation, and can only be dialed in with trial and error.

Bottom line, it sounds like the OP's governor needs, adjusted, replaced, or a smaller pinion installed, if available.

Joe Tondu
02-05-2017, 01:05 PM
Thanks for the ideas. It might be the governor. I was assuming the OD was engaging but on second thot maybe not.

gordr
02-06-2017, 02:11 AM
We need some clarity here. Understand that the overdrive control cable does not "engage" the overdrive. Rather it "enables" the overdrive to function automatically (as it was designed to do), when pushed alll the way in, and disables (locks out) any function of the overdrive, when pulled out. Pulling it even part way out can disable the overdrive. With the cable pushed all the way in, enabling the overdrive to function, it should behave as follows: start out in low gear, accelerate a bit, and llet off the gas, and it should freewheel. The engine will drop back to idle, but the car will continue to roll ahead with no engine braking. Shift to second, it will do the same thing. Shift to third, again it will free-wheel upon release of the accelerator, until the cut-in speed of "about" 27 MPH is reached. Above that speed, let off on the gas, and instead of free-wheeling, you will experience and maybe hear a slight jerk as the overdrive engages, and the engine RPM will drop by 30%, and you will have some engine braking evident, but not much, because of the tall gearing. Cruising along in overdrive, if you need to accelerate fast to pass a slower car, you floorboard the accelerator, and the overdrive "kicks down" to third gear direct, and your engine RPM's take a big jump, and your car speeds up quickly. It will remain in third direct until such time as you slack off enough on the throttle to relieve the torque on the driveshaft, at which point it will shift once more to overdrive. In this way, overdrive behaves about the same as passing gear in an automatic transmission.

Once the speed of the car falls below the 27 MPH cut-in speed, it will kick out of overdrive as soon as the throttle is lifted.

Note 1: You can engage overdrive in any gear. It's unwise to use overdrive in first, because the OD mechanism is not really designed to shift at the torque level of the engine multiplied by the gear advantage of low gear. Routinely using overdrive in first gear will likely break something sooner or later. Such breakage will be expensive. Using overdrive routinely in second gear for racing also constitutes hard usage, and puts it at risk of damage. Driving in traffic, and using the throttle to gently shift to and fro between second direct and and second OD is probably OK, in my personal opinion. Doing that means you only have to use the clutch when you come to a full stop.

Note 2: With the overdrive cable pushed in (enabled), and drving below the cut-in speed, you have free wheeling, and that permits you to shift without the clutch, as long as you are rolling. If you are rolling up to a red light, with your foot off the throttle (braking, even), you can slip the car into low gear without using the clutch, and then simply step on the clutch when coming to a full stop.

Note 3: Cut-in speed of 27 MPH is "nominal". May vary a little, model to model, and can vary A LOT if the overdrive transmission is not mated up to the rear axle for which it was meant to be paired with.

Note 4: Your overdrive is NOT working if you cannot experience a slight jerk, big RPM drop, and slight engine braking effect upon releasing the throttle at a speed well above the nominal cut-in speed, say 40 MPH. If you release the throttle at 40 MPH, and the engine drops back to idle, and the car continues to roll ahead, your overdrive is not engaging. Similarly, if you are cruising along at 60 MPH, and floorboard the throttle, you should experience a slight jerk, and engine revs and noise should increase drmatically, and the car should shoot ahead, just like it would if it were an automatic, and you kicked it down into passing gear. The change in noise level and RPM is very noticeable, going either way, dramatic, even. If you have to convince yourself that you are seeing/hearing a subtle change, then the overdrive isn't working. Thats why overdrive is such a good thing: it dramtically reduces engine noise, fuel consumption, and oil consumption.

TWChamp
02-06-2017, 01:23 PM
Gord explained it well.

I'm just curious why the OP would want to downshift to 2nd at 40 MPH? Were you approaching a steep hill?

GrumpyOne
02-06-2017, 02:03 PM
Gord always answers in detail and accurately. He's a definite example of a helpful neighbor to our north!