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"Hot Wiring a '49 Mercury Overdrive Tranny ?

Discussion in 'The Hokey Ass Message Board' started by TheFrenZ, Aug 11, 2008.

  1. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    '49 Mercury Flathead with stock 3 speed-overdrive tranny.Pre-owner installed a toggle-switch under the dash,you can hear a loud "klick" from a relay underneath the car when activated.

    The governor isn't wired up to the circuit so it seems the overdrive was hot wired.Can this be done without problems and how do I operate this system ?

    From what I heard I go through the gears as normal,then go off from the pedal,push in the overdrive cable and toggle the switch.Correct ?

    How do I disengage the overdrive ? Would like to get some advice before I start checking things.Any kind of help is much appreciated.Thanks !
     
    Last edited: Aug 12, 2008
  2. UnIOnViLLEHauNT
    Joined: Jun 22, 2004
    Posts: 4,814

    UnIOnViLLEHauNT
    Member

    The cable on the lower right side of the dash engages and disengages it. In is engaged, out is disengaged.

    Yes, on a stock setup you would have the lever(cable) in for overdrive. Take off, run out 1st gear, shift 2nd and around 28 mph pull off the gas, listen for the clunk (I swear its a good clunk) and hit the gas again. Now you are in 2nd overdrive. Run that out and shift third. Its still going to be your regular 3rd gear but this time with a .60 reduction behind it.

    I would guess that the toggle puts power to the OD solenoid. I guess you would have to do that the moment you want the OD to work (ie 30 ish MPH) since essentially I think thats what happens? For some reason I want to say that the ground is completed turning the OD on tho, not hot. Hope any of this ramble helps!
     
  3. blown49
    Joined: Jul 25, 2004
    Posts: 2,213

    blown49
    Member Emeritus

    I think the 28 mph only works if it is wired through the govenor (speed switch.) As the Haunt says shift normally thru the gears to above 28 mph, throw the switch and back off of the gas. If wired through the governor it should also drop out at 28 mph
     
  4. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    Thanks Chris and Jim ! Like I said before the governor is NOT wired to the circuit and I understand it's not necessary.However,how do I disengage the overdrive with the toggle-switch set-up ? I know,it may sound like a dumb question but I just want to make absolutely sure I do everything right and don't break the 59 year old tranny...
     
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  5. overspray
    Joined: Jan 14, 2003
    Posts: 1,226

    overspray
    Member

  6. Adam F
    Joined: Jun 19, 2001
    Posts: 323

    Adam F
    Member

    I have been studing overdrive set ups and bypass switches however this is all theoretical!

    I believe that to disengage whilst driving you would need to take your foot off the gas, then hit the switch, which would disengage the solenoid, taking the car out of o/d.


    Adam F
     
  7. zibo
    Joined: Mar 17, 2002
    Posts: 2,347

    zibo
    Member
    from dago ca

    Hi
    This setup works great on that tranny. Its easy once you get used to it.

    First the Lever doesn't actuate the OD,
    it just unlocks the planetary gear used by the OD.
    The switch activates the OD.

    The tranny is in Normal gearing when the lever is spring loaded. (forced position)
    This allows the use of reverse and downshifting.

    __

    The tranny is still in normal gear mode when the lever is sprung, (unforced position)
    but will freewheel or coast when the engine is slower than the tranny.
    Supposedly racers used this mode cause the engine didn't engine-brake between shifts/clutch.
    Tranny won't shift in reverse.


    For OD, switch the solenoid on, with lever sprung,
    let up on the gas and the OD will gear up.
    *The OD will not activate until you give the accelerator a quick on-off-on.

    This is a great trick once you get used to it,
    cause you can be driving, set up the OD lever and switch, way before needed,
    and let up and you get that 4th gear.

    Also, you can be driving in OD,
    flip the switch but don't let up on the gas,
    and say you want to pass or down-gear,
    just let up off the gas and the tranny will powerdownshift to non-OD.
    Its a great driving technique used for passing or on curves.

    Make sure you don't ever use reverse in OD though, it will tear it up.
    Also try not to make it a habit of engine braking with your OD on,
    it wears out the planetary gears or bearings.

    Oh yeah,
    OD can be used in any gear,
    so usually a rolling stop can be made in 1st gear OD, in a rpu anyway.

    Good luck!

    TP aka perichbrothers aka zibo
     
    Last edited: Aug 12, 2008
  8. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    overspray,thanks much for the links.I made a search om here before I started my post and found some of those threads.And yes,of course my car was converted to 12V as well.I forgot to mention that.

    Adam,thanks ! So I just have to toggle the switch again to disengage the overdrive ? Don't have to pull out the cable again to keep the engine from freewheeling ?

    TP,thanks MUCH ! That's GREAT info,way cool.I'm sure I will have a couple more questions for you and you gotta explain the trick with 5th gear a little bit more please ! Also,let's say I drive on an open country road with OD engaged and then have to stop at a traffic light....how exactly do I disengage the OD ? I'm new to this shit,have mercy on me please.
     
  9. zibo
    Joined: Mar 17, 2002
    Posts: 2,347

    zibo
    Member
    from dago ca

    Forget doing an emergency disengage, you kinda have to foresee off-ramps and traffic lights.
    It will downshift to 2nd and 1st anyway if you gotta stop quickly.
    Even then if there're traffic lights you probably won't be getting into OD much anyway!

    _____

    So your in OD and you're gonna stop-
    1. switch OFF the solenoid switch and push in lever.
    2. Let off the gas but then rev it (in gear not neutral) to engage the non-OD gear.
    (!! if you don't rev it weird things sometimes happen like its hard to shift,
    usually it won't go into any gear other than the one it was in, depends on if your moving or stopped)

    You can also just switch off the solenoid switch,
    then off-on the gas and you'll be in non-OD but you'll coast,
    so you'll have to ride your brakes.

    It's really easier than I'm writing it!
    It took me almost 3 years to wear out my tranny not knowing any tricks!

    TP

    I meant 4th gear!
    Let's see some pics of that thing too!
     
  10. Jeff Walker
    Joined: Feb 6, 2007
    Posts: 486

    Jeff Walker
    Member

    Are your sure you didn't meat pull out the lever? All the overdrives I have ever driven, you pull out the lever or cable if you don't want to use overdrive and push it in if you do.

    Also one other tip. Make sure that when you park the vehicle that you have the cable pulled out. Otherwise you will have to make sure that you only park the vehicle in reverse to make sure it won't roll if you are on an incline.
     
  11. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    Unless the solenoid is hooked directly to ground some where else it will never shift into OD with the governor disconnected. The governor completes the circuit to ground once the correct RPMS are reached. The relay can operate (the clicking sound) and send power to the solenoid but with out the ground through the governor the solenoid will never work. If the solenoid ground was rerouted to another ground somewhere then the solenoid would kick in at any speed.

    The governor completes the ground and lets the solenoid engage. You can't just unhook it with out providing another path to ground.
     
  12. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    TP,thanks much for the extra info.I really appreciate it.Thank you !

    Jeff,I'm sure that's what zibo means.Lever out is disengaged,lever in is engaged.And thanks for your input and tip !

    tommy,that's pretty interesting,thanks much ! My car is that low I barely get a jack under it and in the moment I don't know how the set-up looks in detail.I know for sure the governor isn't hooked.I have to check all things next time I drive the car on a lift.Is there any chance you could draw a simple wiring diagram for this set-up ? That would really help to make things bulletproof.Also,you know places where I can get those 12V solenoids ? Thanks again tommy !
     
  13. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

  14. zibo
    Joined: Mar 17, 2002
    Posts: 2,347

    zibo
    Member
    from dago ca

    Hopefully you don't have all that stuff in the diagram hooked up.
    If you hear that clicking then you probably don't,
    since the governor has to spin internally to ground.

    All you need is a a hot switched wire to the activating side of the solenoid.
    Make sure its heavy and has a good fuse on it, the solenoid sucks up juice.
    If you know how to hook up the relay its perfect if your switch is on the dash.

    TP

    Oh yeah JW mine is hooked up custom in a rpu,
    only used a stock setup too long ago to remember if it was the same or opposite!
     
  15. Ramblur
    Joined: Jun 15, 2005
    Posts: 2,102

    Ramblur
    Member

    IMO,wiring the relay through the governor is the only way to go. I t saves
    having to worry about shift out of OD when you come to a stop or shifting to
    reverse. All the governor does(at least in mine) is keep the OD from engaging
    below about 28 mph. I leave my cable in all the time in my Hudson as it runs
    out of rpm in a hurry with the 4.56 gear out back. My relay is powered up
    with a knob(switch) on the dash and red and green jeweled indicator lights
    under the dash. When I turn the knob on the red light comes on and as soon
    as I reach the governor speed the red light goes out and green one comes
    on,then all I have to do is ease off the gas a second and it engages nicely.
    Normally the green light comes on in the top of second gear and I am able
    to shift to third and still stay in direct until I burp the throttle.

    Just my $.02. I heart my OD.
     
  16. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    tommy,thanks for posting those pics !

    TP,I don't have hooked up all that stuff shown in the pic above.Just a switch under the dash with heavy gauge wire,a fuse...maybe...let me check,a relay and NO wires to the governor.I will check both ways...with and without governor and see what works better for me.I'm sure I will have a couple more questions sooner or later...

    Ramblur,thanks much for your input ! Always interesting and helpful to hear several opnions.I appreciate it,thank you !
     
  17. overspray
    Joined: Jan 14, 2003
    Posts: 1,226

    overspray
    Member

    http://www.jalopyjournal.com/forum/showthread.php?t=258186

    Watch the video in the link above.

    I have mine wired stock, like in Tommy's diagram. The governor is a switch. It spins off a gear on the tailshaft and closes the circuit at around 26-28 mph.

    Pulling out the overdrive cable should be done only when stopped. The cable lock outs the overdrive so it operates like a standard 3 speed transmission with compression (engine) braking. In the days when these were new, in town speeds were usually under 30 mph, so running with the overdrive cable in and the car free wheeling under 30 mph with no compression braking didn't give the driver as much control (especially on hills) and he needed to use his brakes more. So in town driving was usually done cable out-disengaged. With todays moderately higher speeds on larger streets, running the overdrive in higher speed traffic works pretty good. As you come to a corner, in overdrive 3rd gear, you have compression braking slowing for the corner and down shifting to second, still in overdrive. As you make the turn and drop below 30 mph the overdrive automatically disengages (the governor/switch opens) and you can accelerate through the corner, in 2nd gear, then into 3rd gear, and then into overdrive.
     
    Last edited: Aug 13, 2008
  18. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    Thanks much overspray ! I value everybodys opinion very highly,cool thing.Can it be you mixed up the video link ? The video shows tips on painting for eyeball.Please try again.Thank you !!
     
  19. overspray
    Joined: Jan 14, 2003
    Posts: 1,226

    overspray
    Member

    Sorry. ---Fixed it.
     
  20. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    When I got my first one several years ago, I stopped for a bite on the way home from work. I hopped out and suddenly found myself trying to prevent my 57 Ford wagon from rolling down the parking lot. Fortunately the grade was not too big and I was able to scramble back in and set the brake before it hit anything. It only has to happen once for you to remember to pull it out of OD when you park.:D

    I'm only 2 blocks from a 50 mph road so I kept it in OD most of the time except when leaving a hotrod gathering so that I could wind it up with the 4.11 gears and let the mufflers bark when I let off of the gas. In OD it just freewheels with no sounds.:D
     
  21. overspray
    Joined: Jan 14, 2003
    Posts: 1,226

    overspray
    Member

    Shifting to reverse with the cable in (engaged) locks out the overdrive. I always put mine in reverse and set the park brake when I park it. It won't freewheel in reverse.
     
  22. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    overspray,thanks for fixing the video link !

    tommy,"funny" story.I always set the park-brake anyway so this hopefully never ever will happen to me.Keep your fingers crossed.

    I just remember one thing from last week when I was out for a test drive...I pushed in the OD lever at around 40 mph on an open country road,engine started to freewheel but there also was a clattering sound like tick,tick,tick,tick....I didn't even toggled the switch,just pushed the brakes and stopped,pulled the lever out and everything was fine again....???

    And where can I get OD spare parts ? Stores like Mac's etc. only carry stuff like the kick-down switch but where can I get a governor or a 12 V solenoid in case any of tha parts on my car are damaged.
     
  23. blown49
    Joined: Jul 25, 2004
    Posts: 2,213

    blown49
    Member Emeritus

    Several years ago my OD (planetary gearset) went out on the Merc. Tried to find a spare unit. Found one at a place in Jersey for around $750.00 (ouch). Decided to look further. Called Borg Warner and talked to a guy that had been there for like forever. He told me the internal unit was used in many cars and if I could find a case that began with a casting number of R10 then the internal gears were the same as mine even though the case and main shaft could be different.

    Went to a local yard and found one out of a Ford PU had the R10 casting number. Asked: how much?

    Response: Not for sale.

    Me: Come on you are a salvage yard!

    Response: Give me $35.00 and we'll put it in your pick-up bed. Take it to your shop and get the parts you need out of it. Put all your old parts back in it and bring it back to me and we'll call it even.

    Couldn't load it fast enough and all the parts I needed were good.

    If you really need to find a replacement I know a guy that has a spare Merc tranny with OD attached that can prolly be bought but not cheaply. PM me for more info Tom.

    Jim
     
  24. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    Thanks Jim ! I hope I can make everything work with the parts I have,if not,I will get back to you.Will check for the clattering sound again next weekend,new oil won't hurt either.
     
  25. thall
    Joined: Jul 12, 2008
    Posts: 49

    thall
    Member
    from nc

    i had read on another forum it is best not to move the cable in motion...
    think it is in this text....

    Over Drive Operation
    <HR style="COLOR: #d1d1e1" SIZE=1 itxtvisited="1"><!-- / icon and title --><!-- message --><TABLE width="100&#37;" border=0 itxtvisited="1"><TBODY itxtvisited="1"><TR itxtvisited="1"><TD vAlign=top itxtvisited="1">Very simple to operate, but there is a no no with these as well, and it can be expensive, here goes.

    First off the cable is to be pushed in to activate the O/D, this can be done while the truck/car is moving, or after you have reached high gear. The no no is never pull the cable out while the vehicle is moving.

    The O/D system consists of the following operations by the driver.
    (1) after shifting into high gear push in the cable, then let off of the accelerator pedal, then push down again, you are now in O/D. This allows the engine about a ball park figure more or less of 30 percent. Example if you are running at 50 mph, lets say at 1800 rpm., the O/D will now give you the same rpm, but another 15 mph faster.

    (2) there is a kickdown switch below the gas pedal, which acts in the same manner as a passing gear. Lets say that if you were running at 40 mph and you wanted to pull out and pass, kick down the gas pedal this takes the transmission out of O/D, and back into your regular high gear. After passing lift up on the gas pedal then push down again normal and you are now back in O/D, same symptoms as an automatic.

    (3) the relay is on the firewall and has a glass fuse I believe either a 20 or 30 amp one, to operate the electrics on the O/D. [​IMG]

    (4) then there is the solonoid, and govenor, which are on the transmission itself. the solonoid locks the O/D, into position, and the govenor will automatically kick it back into the regular 3 speed, at about 26-28 mph, you will hear a light click sound.

    Again never pull out on the cable while moving, you will hear a grinding noise and your not supposed to hear that as you well know.

    All in all its a simple operation, it really is. Usually the gear ratios that are used for these transmissions are 4.11-1, 3.91-1, I have even heard of as low as 3.73-1, it all depends on the type of driving you do, and of course the layout of the roads.

    Hope this will help some of you with answers, on this subject. Just to add something to this the Pertronix Ignition, is a real help to this system. [​IMG]
    </TD></TR></TBODY></TABLE><!-- / message --><!-- edit note -->
    <HR style="COLOR: #d1d1e1" SIZE=1 itxtvisited="1">
    thread here

    http://www.ford-trucks.com/forums/539625-overdrive-in-the-1950s.html

    and yes, shift into reverse to park and set the brake.
     
  26. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    Thanks thall ! The text says not to pull OUT the overdrive cable while driving.I pushed the cable IN to engage overdrive,which is okay and then the clattering sound appeared.However,thanks for posting the text and the link also.You never can have enough info,thank you !
     
  27. with the toggle switch you can pull it out of o/d anytime (not a dead stop only), also the stock set-up it has power to the system (read points inside the gov/solenoid) at ALL times above 28mph (even if you have the cable pulled out). with the toggle my system has no power until i energize it. my toggle switch controls the ground side of the relay. here's my crappy drawing of my set-up.

    to shut off the o/d i push in the clutch, turn off the toggle, then pull out the cable (the power has to be off first or you won't be able to move the cable), let the clutch back out, tap the gas pedal (this is when it dis engages), if your engine is slowing you down then your out of o/d (if it still freewheels hit the gas again).
     

    Attached Files:

    Last edited: Aug 13, 2008
  28. Jeff Walker
    Joined: Feb 6, 2007
    Posts: 486

    Jeff Walker
    Member

    As long as you aren't in overdrive you should be able to pull the cable out with no problem with no problem. My dad had several overdrive cars through the years and I remember seeing him doing that countless times. IIRC he also did it with the engine under power and not coasting which would keep the vehicle from going back into overdrive.
     
  29. blown49
    Joined: Jul 25, 2004
    Posts: 2,213

    blown49
    Member Emeritus

    IMPORTANT!!!!!!!!!!!!!

    Tranny case and OD unit case each have separate oil fills.
     
  30. TheFrenZ
    Joined: Dec 3, 2004
    Posts: 1,898

    TheFrenZ
    Member
    from Germany

    Thanks Jim ! Yes,I'm aware of that.

    1oldtimer,thanks much for the drawing and info ! Really cool,helps a lot,thank you !

    Jeff,thanks again for your input ! You guys are phenomenal !
     
    Last edited: Aug 21, 2008

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