Need simplified OD wiring circuit

[Charlie ny]

Guys,
I build OD trans all the time but never been asked to wire one.
My customer is attempting to describe a simplified circuit that does away with the governor, does not include the kickdown etc. I know this is possible
but I'm unsure of how to do it.



Gracias,
Charlie ny

[leon bee]

Not much help, but over on the HAMB I've seen discussions of alternative wiring for these with different setups. I hadn't considered differing from Ford's scheme for my 50 car, but I got kinda interested. Anyway, been talked about over there.

And I think that Randy Rundle book mentions a couple things NOT to do.

[tubman]

I have a book at my shop that has this information. I'll find it tomorrow. I seem to remember that it will work OK if you do things properly and in the proper sequence, but risk ruining components if you don't.

[expavr]

Charlie
I ran a a 10 gauge wire from the ignition switch to a 30 amp inline fuse to an On/Off toggle switch (30 amp) to the solenoid on the 49 Merc O/D transmission in the Tonner.
Les Williams

[Willit Stop]

Maybe this will help:
http://www.btc-bci.com/~billben/flathead.htm

[Willit Stop]

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Hmmmmm.Maybe not. Sorry.

[Frank Miller]

What Les said but there are two wires on the solenoid and it need to go to the one for the coil not the kickdown. One terminal will show open and the other will show some resistance to ground. That is the one you want.
That being said he better make sure that thing is switched off when backing up or it's toast. That governor serves a purpose and the kickdown feature is loads of cool. It's not complicated by a long shot to do it the right way. I mean factory way.

[rotorwrench]

Removing the automatic features make the operation sort of like a two speed axle on a truck. If a person split shifts then the switch will get a lot of use. If A person only uses it for top end OD then the switch only gets used to pop it in and take it out of OD. A person can drop it down out of OD easy enough if they let of the throttle before turning off the switch. Not as fast as kick down but it will work. Your switch has to be where you have easy access to it. If a person converts to a three speed stick shifter, a switch for a two speed axle can be attached to the stick for easy access.

A person has to remember to turn off the switch before coming to a stop or shifting into reverse. This is where problems can arise. I think I'd use a circuit breaker rather than a fuse on a circuit like that.

[Kahuna]

As mentioned, make sure that it's OFF when shifting to reverse

[40 Deluxe]

Wait a minute! Every O/D trans I've driven has an internal rod that makes it physically impossible to shift into reverse when the unit is in overdrive mode Try it!

For that matter, why in the world would anyone even want to disable the governor, or the kickdown feature? That is just backward! Of no useful purpose! Wire it right and enjoy the automatic features that are built in!

[rotorwrench]

A person may have a problem getting it into reverse if the pawl is partly engaged. The lockout rod may not engage the slot in the pawl if it's against the balk ring. If it did go into lockout then a funny thing will happen when you put it into first gear and try to move forward. It will likely just freewheel and not go anywhere. I've never had this happen but I wouldn't want to try it. It takes a bit of work and frustration to get in to go back into the overdrive off position when this happens. If I remember correctly, a person has to push the car backwards a bit to get the pawl to back out.

[40 Deluxe]

When a teenager I wired a toggle switch to the governor wire so when 'on' it allowed overdrive at any speed, even at a standstill and served as a hillholder because the trans locks up going backward when O/D is engaged, even in neutral. I thought I was pretty smart until one time at an uphill stoplight the car ahead rolled back toward me and I could not get out of the way!

[Hyvolt]

I have just recently finished wiring my od in my 41 deluxe. I used a trans from a 49 merc, and used a modern relay that is controlled via the governor. The only modifications that i made to the original set up is that i used a switch in line with the governor to keep the system off when needed, and i found a smaller push button to cause the kick down when i wanted it, unlike the original under the throttle setup. Works great, and is lots of fun. Leave the switch on, factory operation. I am working on a diagram, just not done yet. I can give you a quick sketch and some pics and part numbers for my parts if interested, can't get to it till next week cause the holidays are busy. I also used some indication lights, so you can watch it work!

[Charlie ny]

Hyvolt,
I would very much appreciate your diagram along with part numbers. This
will be a spring time job. The trans is a T 85 monster and I too thought the kick out linkage would protect the OD regardless of wiring when shifting into reverse.

Thank you all,
Charlie

[Mike51Merc]

Originally Posted by 40 Deluxe

Wait a minute! Every O/D trans I've driven has an internal rod that makes it physically impossible to shift into reverse when the unit is in overdrive mode Try it!

My '51 Merc will shift into reverse with OD engaged, for sure. I have a toggle switch to engage the OD and I have (despite knowing better) left it in the "OD on" position and tried to back up. The moment you release the clutch you can feel the binding. At that point if you keep releasing either the engine is gonna stall or the sun and planets are going to implode.
I'm a fan of the original system or a modern substitute. It's good protection from a bad memory.

[Charlie ny]

I'm now convinced the Ford circuit must be implemented.....thanks guys.....
I need a source for a modern relay & finally can the kick down feature be eliminated ?
I certainly wish to give my customer what he wants and it's good from my perspective to be able to articulate arguments against his point of view.
Many thanks,
Charlie ny

[Frank Miller]

Yes the kickdown feature can be eliminated. That will mean no need for the switch or wiring from the coil. The governor will merely ground the relay contact switching on the solenoid. You will only use the one wire on the solenoid as I stated before. If he is running 12 volt then any 20 amp switching relay will work.

[tubman]

Better late than never. Here is the "simplified" OD wiring diagram from the "Thunder Road Flathead" book by Bill Sinclair. There are a couple of pages of text as well if anyone is interested.

[40 Deluxe]

Originally Posted by Charlie ny

I'm now convinced the Ford circuit must be implemented.....thanks guys.....
I need a source for a modern relay & finally can the kick down feature be eliminated ?
I certainly wish to give my customer what he wants and it's good from my perspective to be able to articulate arguments against his point of view.
Many thanks,
Charlie ny

If your customer has never driven a car with fully functional overdrive (including kickdown), encourage him to go for a ride in a car with working O/D and a driver who knows how to use it. Be sure to get a demonstration of using the kickdown (or "passing gear"); it has the same effect as flooring the gas with an automatic. In town with 30-45 MPH speed limits, 2nd gear overdrive is great! In overdrive the engine is loafing and if you need a quick burst of speed to avoid a texting driver, just floor the gas and you've immediately dropped a gear. No need to lose precious seconds getting off the gas, pushing in the clutch, and moving the shift lever. Just instant response!

[expavr]

“My '51 Merc will shift into reverse with OD engaged, ”

That’s interesting. On the 49 Merc transmission with the mechanical linkage pushed in to allow the O/D to function you can’t engage reverse. I just checked it and the shifter linkage encounters enough resistance that to engage reverse you would have to use serious force to do so if its even possible.
Charlie
I think the “toggle”vs “no toggle” debate depends on how the owner intends to use the O/D and whether or not they have all the parts to make it function. Decent tailshaft governors are hard to find which was a problem at the time I rebuilt my trans and dictated the simple wiring circuit I use. I use the O/D in the tonner as a 2 speed brownie engaging it mainly on open highways and freeways where road conditions over 50 MPH make sense to use it otherwise its locked out. The learning curve isn’t that steep and its relatively easy to either grab a gear or toggle the O/D off if more engine RPM or torque is needed. JMO.