Just now getting around to addressing the overdrive on my '50 Merc. According to the Randy Rundle book (if I'm reading it correctly) whether or not any of the electrical components work, with the overdrive cable pushed in, the car should freewheel when I let up off of the throttle at speeds of over 28 MPH or so...correct? What I can't ascertain from the manual, is that if the car doesn't freewheel with the cable pushed in at over 28MPH, what the mechanical issue might be and how to go about fixing it. The Merc goes thru all the trans gears fine, I don't hear or feel anything out of the ordinary, (like gears clashing or bearings crunching) but it has never (since I've owned it) "freewheeled" in gear. If I let up off the gas at 15 or 50, there is engine braking happening. I haven't done all of my electrical testing yet, although I did check the solenoid and it does work...as does the governor...haven't checked the relay yet...but if the overdrive is broken internally, then there's really no point in continuing on down that path at least for now. Any ideas on what might be the problem, or what I can test/check to see if the OD has, in fact, failed internally? Operator error? Thanks... CH
I've been saving the OD on my 50 Ford until having most every other mechanical thing dealt with. If I just sit here and read the book, without my hands on any of the parts, it just makes my head swim. If there is no juice at the governor, either in or out, it ain't doing anything, right? So the 28 mph has no bearing at this time? If I drive that car tomorrow, (no OD stuff is hooked up) maybe I'll reach underneath and engage the lever at the trans and see what happens.
The trans should not freewheel above 28mph, but rather BELOW 28mph. You should be able to compression brake above 28mph going down a hill...as the speed drops below 28 due to braking action, the trans will freewheel until about ~3 mph. The freewheel action is why the trans must be in Reverse gear when parked; otherwise it will roll.
Also forgot to ask, does the car go into overdrive above 28mph when you let off the throttle? If so, When at hiway speeds and you mash the throttle (when in OD), does the trans kick down out of OD? All the above assuming the cable is pushed in.
"The Merc goes thru all the trans gears fine, I don't hear or feel anything out of the ordinary, (like gears clashing or bearings crunching) but it has never (since I've owned it) "freewheeled" in gear. If I let up off the gas at 15 or 50, there is engine braking happening." I wonder if you have the cable hooked up correctly. What happens when you pull the OD cable OUT? How does the transmission act?
NEVER put the trans in reverse with the cable pushed in NEVER. Go under the car with the cable out and have someone else push it in making sure the arm goes all the way to the other side. Yes, the trans will freewheel or not have engine braking BELOW 28 mph. The arm goes towards the rear of the car in o/d and towards the front locked out of o/d.
For the OD to work on my Chevy, the cable must be pulled out. But whatever the case, I would make sure the cable moves the lever correctly and completely. This is step one, if the lever doesn't move far enough, no OD/freewheel. After that continue to investigate the electrical component.
It does not go into overdrive, but that's likely due to a bad relay or connection. However, before I spend more time rewiring and money on a new relay, I'd like to figure out if the overdrive will even function mechanically.
I think so...unless the lockout lever on the trans is 180 degrees upside down...if that's even possible...
Disconnect the cable at the arm on the trans and flip it the opposite way (all the way) and try it. If it doesn't freewheel, try the other way.
Uh-Oh! Too late for that! The cable has been pushed in ever since I got it...besides, I thought there was a rod connected to the reverse lever (internally) on the tranny that automatically locks out the overdrive unit when it's put in reverse. As I understand it, the only way to damage the OD in reverse is if the solenoid pawl isn't disengaged when shifting into reverse--thus the "no-no" of installing a toggle switch for the solenoid instead of routing through the governor.
Here's how my 50 acts with NO electric hooked up anywhere: cable in/lever flipped to the back, car does the freewheel on decelleration at any speed. 50mph or 15mph, it does the "freewheel". On mine, that reverse with cable in is not an issue. Putting the trans in reverse slides that lockout deal inside.
There is, unless the parts are missing. I make it a habit not to use reverse with the cable in, just in case.
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