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Projects Wiring a T85 with overdrive in a truck

Discussion in 'The Hokey Ass Message Board' started by Chris, Mar 5, 2018.

  1. hello. I have a decent BW T85 three speed transmission with an R-10 overdrive unit. I somewhat understand how these work...but originally there is a governer, kick down switch, cable operated lock out and the solenoid.

    Has anyone ever put one of these into a car and just wired the solernoid to a toggle switch bypassing the governer and kick down switch? If so, how did you wire it? I am not an electrician at all, so sorry if this seems kind of dumb. I want to replace the 4 speed in my 1959 F-100 with this unit

    Also, does anyone know how to test solernoids?

    5B981C95-41ED-4ECA-AA76-E156AEE6253E.jpeg D5FED987-C523-4344-A8D1-7439828A3972.jpeg
     
    chryslerfan55 likes this.
  2. I ran that same set up in my '51 F1 for quite a few years. Simple 12 V toggle switch on the dash providing a 12V powered wire to the solenoid. I would accelerate up to speed, hit the switch, take my foot off the gas, and the transmission would shift. Put my foot back on the gas, and turn the switch off. The transmission would stay in gear as long as there was a torque load. If you took your foot off the gas, or depressed the clutch, you would have to re-engage the switch or the transmission down shifted into 3rd automatically. I never left the switch on for long periods of time for fear of burning out the solenoid, although supposedly, you could.
     
    Last edited: Mar 5, 2018
  3. It's easy to wire one bypassing all the controls, but they work better if you don't.
     
    Hnstray and squirrel like this.
  4. J Twitero
    Joined: Apr 15, 2011
    Posts: 105

    J Twitero
    Member
    from Minnesota

    My old Ford did not originally come with OD, but I added it in. I literally found a switch rated for 30amp (which is what the stock fuse was), added a fuse holder and wired it direct to the solenoid. It adds a bit of complexity to driving, you have to pay attention to when you want overdrive and when you dont, but it works well. I am still running 6v system in mine, so make sure you have the proper solenoid there are both 6v and 12v versions.
     

  5. J Twitero
    Joined: Apr 15, 2011
    Posts: 105

    J Twitero
    Member
    from Minnesota

    I will add when I bench tested my solenoid out of the transmission, I just hooked one jumper cable to one of the mounting ears, and touched the big terminal with the other cable (pos vs neg). There is another terminal on the solenoid that was to ground the points for it to shift automatically if wired up "stock". I dont recall if they were the same size or not, so maybe try both terminals if it doesnt actuate.
     
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 47,823

    squirrel
    Member

    I put one in a 59 edsel, I wired it up mostly like it's supposed to work. Used a horn relay to run the solenoid, the "horn button" contact on the relay connected to the governor, grounding the relay coil when it gets up to speed, which then powers the solenoid. Letting off the gas lets it shift into OD, after it's up to speed. I even connected a microswitch as a kickdown switch, although I put it on the shifter, not on the throttle linkage.

    I guess Crazy Steve and I are total wiring nerds, so this stuff is pretty easy for us.
     
    Hnstray likes this.
  7. The BW OD as-designed and installed is an excellent transmission as long as you understand it's two major shortcomings. One, it doesn't suffer abuse well. Beat on one, and you'll be rebuilding before too long. I've killed them behind bone-stock sixes...
    Two, lack of engine braking while in OD due to it's 'free-wheeling' design. Yes, there's a small amount of braking, and if you live somewhere that's flat it won't be an issue. But go down a long hill in OD (like a mountain pass) and you can run out of brakes before you get to the bottom. BTDT, and it ain't fun.... This is one of the reasons the BW OD disappeared; the OEM manufacturers considered this a safety issue, which it is.

    Wiring one up to OEM design isn't hard (wiring diagrams are all over the 'net), the main hangup is the kickdown switch. Being a 'specialty' switch, you can't just buy one anywhere, and the mounting of it seems to flummox guys who have no problems fabricating other parts. You can get around a lack of the OEM-style switch with relays, but it does complicate the wiring somewhat. If you have electronic ignition that can complicate the wiring also, but isn't an insurmountable obstacle.
     
  8. J Twitero
    Joined: Apr 15, 2011
    Posts: 105

    J Twitero
    Member
    from Minnesota

    I did collect the other bits out of the car that I took the transmission from for mine, but both the kickdown switch and the relay had issues. Trying to locate new ones easily (all of it is available online) to get it working proved difficult as none of the local parts houses list any of it. I found a heavy duty switch, wired it up to get it working, and found I am more willing to live with flipping a switch when I want OD than trying to get it set up stock. I find that once I'm up to speed and in OD, I dont even long for the kickdown feature that often up here in central MN. That may change in hillier areas.
     
  9. If going with a full manual wiring set-up, you do need to be careful about engaging/disengaging the OD to make sure it isn't under load when you do that. Under some circumstance it can damage the trans...
     
  10. That's guys, I am not a wiring nerd. I don't understand a lot of it, I do not know what a micro switch is. to me it looks like a switch that cuts out only when pressed? I get the mechanical side of the transmission and what the lockout cable, solenoid, kick down switch and governor do. But I do not really understand what a relay does. So when Jim says he used a horn relay, I do not understand why that works vs the original (expensive). Are relays the same as long as they are the same AMP? and of course the original had 4 connections. I wish I understood more of that stuff but I have not had much experience with it...hence wondering if I could half ass wire it HAHA! Thank you for the input, I found wiring schematics online and I agree it would be pretty simple to wire how it was intended if you had everything and it all functioned. I actually found an older post Jim (Squirrel) did on this same subject.
     
  11. The relay used on most OD set-ups really isn't anything 'special' other than the fact they include a place to install a fuse. You can substitute a common parts house 30A 'headlight relay' easily, you just need to mount the fuse somewhere else. All a relay is, is an electrically operated switch, generally used to allow a light-duty manual switch to be used to control a higher-amperage circuit via the relay(s). They're also used to operate multiple circuits with single-point control, i.e. one switch can control more than one relay/circuit.

    The typical kickdown switch is special; it consists of two single-pole switches linked mechanically. One switch is normally open, one is normally closed, when operated they change states. This single switch controls two separate circuits, and it's technical description is 2PST-1NC/1NO. Jim referring to a 'micro switch' is just describing a type of switch that is included in the larger 'family' of 'limit switches' which is how they're commonly referred to. There's literally dozens of mechanical style limit switches available, although they're generally not cheap once you go beyond 'basic' switches. If you get into electronic limit switches, there's hundreds of types.

    If there's enough interest, I could draw up and post diagrams on how to make it work without the OEM relay and/or switch. The relays aren't expensive (about $10 each) and a 'basic' mechanical limit switch is even less.
     
    cactus1 likes this.
  12. I would like to see a diagram for sure! I am going to run a Columbia rear in a project eventually and I assume I could use a similar set up?
     
  13. I know zip about Columbia two speed rear axles, so whether this would 'cross over' is hard to say....
     
    cactus1 likes this.
  14. 325w
    Joined: Feb 18, 2008
    Posts: 5,490

    325w
    ALLIANCE MEMBER

    What do you do if your running a MSD electronic distrubitor. Can you allow the OD to go to ground as designed. Will the MSD tolerate the grounding?
     
  15. squirrel
    Joined: Sep 23, 2004
    Posts: 47,823

    squirrel
    Member

    nope. I would not bother with the ignition cutout, just back off the throttle for a moment
     
  16. If you want to retain the kickdown feature, a relay can fix the issue.
     
  17. squirrel
    Joined: Sep 23, 2004
    Posts: 47,823

    squirrel
    Member

    but don't connect it to the coil, connect it to the wire that goes to the MSD box from the ignition switch.
     

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