OD or Not?

[Bob Riding]

Last year I purchased a George Asche OD unit (he took my P10 tranny and went through it and added the OD parts, etc). I was planning on using it in the P10 wagon, which has a stock 4:10 rear end. I also got a free 1950 Plymouth rear end last year that says it's a 3:73.

After all the problems that some folks have had with OD units, I was thinking I could sell the Asche OD tranny and just use the 3:73. The engine will be a 230 from a Dodge B2B and 16" tires. The simplier, no OD setup seems like way less hassle, but the OD (if working right) seems cooler.

What would you do?

Thanks

Bob

[oldmopar]

Easy answer for me I like to keep things simple so I would just go with the rear. Although I think a 3.5 or 3.2 would work even better for highway.

[Young Ed]

3.73 with 16" tires will get you going nicely. Dad used to have a 39 ply with that setup and his only had a 201.

[Plymouthy Adams]

I have a 230 with 3.73 gears and it is very confortable at 70...however...with the OD ...the installation of the unit is such a simple task..why not install it and give it a whirl..I mean you have already bought and paid for it..of all the units he has sold....he still has a good track record...the OD will give you cruise speed at a comfprtable RPM and better fuel economy..anytime you can work your engine in the lower band..the better off you will be in the long run.

To run similar RPM without the OD will take a Dodge Dakota rear gear of 2.94 ratio...there is the loss of power in first gear pulling off to consider..this will not be lost with the OD.

[Jim Yergin]

Bob,

Other than James Douglas' problems the only other O/D problem I have seen on this board was Normspeed's corroded fuse connection. Have there been others that I missed?

Jim Yergin

[Young Ed]

I think Pete had some wiring issues when he first got going but otherwise I think everyone seems to be good. My 51 OD worked the one time I drove it fast enough to try it. Dad has 2 that work fine as well.

[blueskies]

I say if you have the OD in hand, you might as well give it a run.

Out of all the OD's Asche has sold, how many of them have you heard about having issues? Seems to me the problem is with his "service dept", not the overdrives... generally speaking.

Asche supplied a rebuilt OD for Hans Reinhard's '50 that was driven from Peking China to Paris France.

Over 10,000 miles of the worst conditions imaginable. If you think the streets of SanFranciso are bad, try Mongolia... The OD performed flawlessly.

I love my OD, I can't imagine my car without it. It is what makes it truely roadworthy, imho.

Give it a try, you've got nothing to lose but a few hours swaping it back out if it does't work.

Pete

[blueskies]

I think Pete had some wiring issues when he first got going but otherwise I think everyone seems to be good. My 51 OD worked the one time I drove it fast enough to try it. Dad has 2 that work fine as well.

The wiring issues I had were my fault...

The first was the kickdown switch, which momentarily grounds the ignition. My HEI and fuse block setup didn't like this at all, and just blew the fuse to the igntion when I hit the button. I've re-configured the kickdown switch, and no longer need this part of the circuit.

The second was a faulty ground in the system. I have my relay mounted up under the dash, above the e-brake handle. The first time I drove it, it would not enguage and I couldn't figure out why. I ran through the trouble shooting guide in the Borg Warner book, and found that the cause was the system was grounded, when it wasn't suposed to be. After getting my head back up under the dash to look at the relay, I found that I had mounted it so that one of the contacts was touching the body of the car. Moved it over slightly, and it has worked fine ever since.

I have about 14,000 miles on my OD, and it works great.

Pete

[Suddensix]

No brainer, go with the OD, best piece I ever installed on my P18.

[james curl]

I have a 3.55:1 Dakota rear end in my 48 Plymouth with 218 in engine and I took a 4600 mile trip in it last summer. The car has P205 75 15 tires and cruises 70 mph at 3200 RPM. Your 4.10 rear end and over drive should cruise 70 MPH at 2465 RPMs in OD with 670 16 tires. With the 3.73:1 rear and 670 16 tires you should cruise 70 at 3200 RPMs. The 4.10:1 with the 670 16 tires should cruise 70 MPH at 3520 RPMs which is a little high for a straight 6 for long periods of time.

[Normspeed]

I sure enjoy mine. They're not for everyone though, as they don't behave like an ordinary 3 speed in some conditions. Like, if your OD is engaged with the dash handle, and you are decelerating using engine compression, when you drop below governor speed it will seem to go into neutral until you are almost stopped. (free-wheeling). It's supposed to but it can be disconcerting at first. Mine was a factory install, so it didn't cost me anything, except $300 or so in parts when I freshened up the trans and OD.

If I had the ways and means that Don C has, I'd go with a T-5, but I don't have access to the kind of machine shop expertise he has.

Bottom line, if I were you and already had a reconditioned one ready to go, I wouldn't hesitate to install it. If you wire in a switch like mine or Pete's, it's a hoot to drive around town using it as a 5 speed.

[Don Coatney]

I have a 3.55:1 Dakota rear end in my 48 Plymouth with 218 in engine and I took a 4600 mile trip in it last summer. The car has P205 75 15 tires and cruises 70 mph at 3200 RPM. Your 4.10 rear end and over drive should cruise 70 MPH at 2465 RPMs in OD with 670 16 tires. With the 3.73:1 rear and 670 16 tires you should cruise 70 at 3200 RPMs. The 4.10:1 with the 670 16 tires should cruise 70 MPH at 3520 RPMs which is a little high for a straight 6 for long periods of time.

James;

Do you not have an overdrive in your car?

I have a 3.55/1 differential, running P205-75-R-15's. With my T-5 in top (overdrive) gear I cruise at 70 MPH turning 2200 RPM's.

Bob;

In my opinion an overdrive transmission is the only way to go in these vintage cars. I can (and have) run 70+ MPH for hundreds of miles. Could not do that without an overdrive. I am waiting to hear if James Douglas was correct in evaluating his problem. But as has been mentioned there are a lot of GA rebuilt overdrives on the road.

[40phil41]

Bob,

I have a 3.73 in my '41 (with 16 in. tires) and an OD in my '40 (with 4.1:1 and 16 in. tires). I can't really tell the difference between them. Took me a while to get the OD working due to a lazy solenoid and not heavy enough gauge wire to the solenoid. After that it works just fine. I found the OD a bear to jack up and install from underneath the car but since you are building your wagon from the ground up I would go ahead and install the OD.

Phil

P.S. What I will do when the '41 comes out of winter storage is to measure the R.P.M. vs. speed of both cars and see how they actually compare.

[martybose]

The wiring issues I had were my fault...

The first was the kickdown switch, which momentarily grounds the ignition. My HEI and fuse block setup didn't like this at all, and just blew the fuse to the igntion when I hit the button. I've re-configured the kickdown switch, and no longer need this part of the circuit.

(snip)

Pete

A while back someone had published a wiring diagram that used modern Radio Shack relays to run the overdrive circuit. The one thing it didn't have was the ignition kill part of the circuit.

I've been doing some research, and may have found a relay that I could use to interrupt the power to the coil on my HEI setup. I'm going to source all of the relays from McMaster-Carr. When I get around to trying it out I'll let everyone know.

Marty

[blueskies]

A while back someone had published a wiring diagram that used modern Radio Shack relays to run the overdrive circuit. The one thing it didn't have was the ignition kill part of the circuit.

I've been doing some research, and may have found a relay that I could use to interrupt the power to the coil on my HEI setup. I'm going to source all of the relays from McMaster-Carr. When I get around to trying it out I'll let everyone know.

Marty

Marty-

I was going to investigate some sort of solution to interrupt the power to the HEI, which momentarily takes the torque off of the system so that the solenoid can move. But after driving it without this setup, I found I like it much better. Instead of a full throttle kickdown, sort of like a modern automatic, I have to release the throttle while pressing my kickdown button to shift out of OD. I can now "split-shift" the OD, using all five forward speeds. And I find that I shift out of OD often in situations where I would not want to give the engine full throttle.

Pete

[Bob Riding]

Great advice. I think I will use the OD and the 3:73 rear. Seems like a desirable combo...thanks to all for the advice...one more question - what is the best way to engage the OD? Asche's "kit" came with a 3 way toggle switch that needs to stay in the center when not engaged...that seems awkward. I found a switch on e bay last year where you replace the knob on the shifter rod and it has a button in the center, however, it's only got 1 wire instead of the 2 that George’s diagram shows...

[Jim Yergin]

Bob,

I am using the same gears shift knob switch on my set-up. However you will need to use a relay since the switch is normally open whereas the kick-down switch is normally closed. Pete Anderson had the same situation with his switch and you can see his explanation on his web site. I am using the switch to trigger a relay that is normally closed. I could only find a 12 volt relay but I have a 6 to 12 volt inverter for my FM radio and this relay.

You might want to consider keeping the 4.1 rear end. That way you will have the advantage of quicker acceleration and more power in non-overdrive and the better fuel economy and less rpm in the overdrive mode. I look at it as the best of both.

Jim Yergin

[Bob Riding]

Jim; Good point on the advantages of both the OD and the 4:11. Do you have Pete Anderson's web address?

thanks

Bob

[Jim Yergin]

Bob,

Pete Andserson is Blueskies.

http://www.50plymouth.com/

Jim Yergin

[blueskies]

...I found a switch on e bay last year where you replace the knob on the shifter rod and it has a button in the center, however, it's only got 1 wire instead of the 2 that George’s diagram shows...

Bob-

The factory kickdown switch is a two circuit switch. One circuit controls the relay/solenoid, and the other momentarily interrupts the ignition at the coil, taking the torque off of the transmission so that the solenoid can release.

This setup is designed to work as a full throttle kickdown, and the factory kickdown switch is meant to be mounted on the throttle linkage. When you mash the pedal, the button is pressed, and the system comes out of OD.

The way I have my kickdown wired, is slightly different. I eliminated the coil circuit all together, and am only using the relay/solenoid circuit. What is then different, is that I have to release the throttle while pressing the button, to shift out of OD.

I mounted a small micro switch from Radio Shack on the end of my shifter, to work like the factory button you found on e-bay. The problem, is that the switch is normally open, whereas the factory switch is normally closed. Thus, the switch worked backwards. To solve this, I bought a relay, and wired it so that the switch on the shifter controls the relay, and the relay does the switching for the OD wiring.

I really like my setup, because I can "split-shift" up through the gears, using all five forward speeds. I start in first direct, accelerate up and then shift manually into 2nd direct, accelerate again and release the throttle automatically shifting into 2nd OD, accelerate again and this time, shift manually while pressing the button on the shifter coming out of OD and into 3rd direct at the same time, accelerate again and release the throttle automatically shifing into 3rd OD.

I didn't like having to accelerate to downshift with the factory wiring setup.

I'm not sure what the extra toggle is for on George's wiring harness... I see no need for it.

It seems that this three way switch eliminates the governor from the circuit if in the center position, preventing the OD from engauging. In the right postion, it allows the governor to function as the factory intended. In the left postion, it allows the OD to engauge below the cut-in speed or makes the OD stay enguaged when you drop below the cut-in speed of 27mph. The lockout cable does the same thing as having the switch in the center postion, so I'm not sure whay you'd need that. I can't think of a reason to engauge the OD under the cut in speed. I'm also not sure why you'd want to complicate the use of the system for the driver, having to remember what the switch is for and what position it is supposed to be in under what conditions.

The factory wiring is meant to work seamlessly without much though on the part of the driver... and it works great.

Pete

[Don Coatney]

Pete;

Got the red x's again???

I posted this and after doing so your pictures appeared????

[blueskies]

Pete;

Got the red x's again???

I posted this and after doing so your pictures appeared????

It's a complete mystery.... Seems that you have to reload the page to get the images to appear.

Pete

[jd52cranbrook]

I am running 12 volts, with HEI. The wire harness and fuse box is from Kwik Wire. The coil is also in a fused circuit as Pete's, however mine does not blow the fuse when used. You may want to investigate your wiring in that area Pete?.

I did go with the two relay set up that James Douglas posted a while back, (I have since sent James a email thanking him for posting it, and to apologize for any negative post by me concerning his OD problems with his vendor ),

At any rate, the kick down is awesome with this set up. I can kick down at any RPM now, even in 2nd gear. And can also go the 5 speed route when inclined to do so. Works just like my Dodge Hemi Ram when wanting a lower gear for downhill, etc.,,,,,

[Normspeed]

Mine is still 6 volt. I retained all the factory stuff including the kickdown switch on the carb but since I installed "the switch" AKA "big ugly", I never use the kickdown. Instead I flip the toggle and let off the gas, to go into or out of OD. No relay, just a heavy duty switch and 14 gauge wire inline with the governor circuit.

The switch lets me drive it like a 5 speed when it suits me or a regular 3 speed.

[HughForrest]

Bob-

I have a G.A. overdrive with a 4.11 rear in my 50 woodie that you'd be welcome to test drive if you make it to Santa Cruz. It is very happy at freeway speeds.

Hugh