Hello Don

Drivemaster consists of TWO vacuum operated units.

One does the [u]automated clutching [/u]and by itself, was called VACUMOTIVE DRIVE. In your first pic, it is the lower unit with the larger vacuum cylinder. Normally, this unit is installed on or near the left side of the cylinder head in the engine compartment.

The second unit does the [u]automated shifting [/u]and again in your first pic, it is the unit at the top with the smaller vacuum cylinder. Typically, this unit would be located underneath the floorboards adjacent to the left side of the transmission.

When both of these are installed on the vehicle and ARE properly coordinated the combination was called DRIVEMASTER. DRIVEMASTER supplied automated clutching & shifting between second & high gears. This answers your question. YES, they do work together

I hope this helps

Joe Ritter

Don: Listen to Joe, he's the MAN! Not only does he know about them, he rebuilt one of these and put it in his '47!

Thanks Joe for the reply would you happen to have any pictures of your installed drivemasters?

Don: As you will see in the attached pics, my '47 Super is equipped with only the Vacumotive Drive, i.e., the automated clutching portion of Drivemaster.

After activating the unit by using the dash switch one needs to operate only the accelerator and brake pedals for starting off, shifting while moving and stopping. However, all shifting must be done manually.

Joe

Does anyone have the mounting brackets for these two units that are for the stepdown eight? I have two each of the clutch and shifting units, both for a stepdown 6. I have rebuilt a set and all I need is the linkages and brackets for the 8..

do you have a part number for the bracket

There's a Drivemaster service book in the online library -
http://hetclub.org/burr/lithomepage.htm - it's in the Other H-E-T Literature file at the top of the page.

Hudsonly
Alex Burr
Memphis, TN

Don,
Here are the part numbers that are 8 cyl. only.. I gleaned these from the 48-54 parts book. I omitted the simple hardware stuff. Any help would be appreciated.
The illustrations I found were generic.. six cylinder. Not much help there. I did get a couple pictures from a few members a while back that helped me some.

Shift portion:
3011238 Clutch power unit bracket, complete
301585 Vacuum pipe assy, power unit end
301548 Intake vacuum pipe assy

Clutch Portion:
301438 Clutch power unit brackets, complete.
300895 Spacer, Cyl. mtg brkt.to water jacket.
301544 pipe assy, VD & HDM clutch control, manifold end
301545 pipe assy. valve end
300908 Threaded sleeve rod assy.
300911 Rod Accelerator switch to cross shaft.

I have a 46 with Drive Master installed...or at least everything on the dash panel is there. I just got the car 2 weeks ago and haven't started it yet but I'll get some pictures for you if you like.

Keith,

Pictures would be great!

Hi Guys,
Ok so upon futher investigation, things get a bit more confusing. I have the Drive Master dash panel with swithes (I'll post the pict) but when I took it out, all the switches were disconnected (though the wires were still there). Looking under the bonnet, the parts seen in the pictures in the first post of this thread aren't there.
Here's where it gets more confusing. The guy I bought it from said that the Hudson has OD. I've been told OD was part of the Drive Master system, I've also been told it was a totally different tranny. I found a receipt in the docs I was given for the car which a repair shop installed a switch under the dash (for OD, up position is ON, down is OFF). I also recall the guy I bought it from saying he'd driven the car in OD, but it was confusing.
I'm guessing the DM was removed at some point, and either a different tranny installed or, if some ppl are correct, the OD aspect was kept. What do you all think? I was really looking forward to trying to drive the car with the Drive Master!

Overdrive is a type of transmission that couples a fourth gear to a regular three-speed transmission. You shift manually through the three gears, then (when the overdrive is enabled by pushing in the OD knob) you can shift into fourth gear by lifting your foot off the accelerator temporarily. It's not an add-on device. It is constructed at the factory.

Drive-Master is a factory add-on device by Hudson that shifts your three-speed transmission semi-automatically. It has nothing to do with an overdrive.

"Super-Matic" was a Hudson option that blended Drive-Master with an overdrive transmission, to get you four gears semi-automatically. It required that an overdrive transmission be installed in the car. Super-Matic was a Drive-Master variation, a gizmo that bolted to the engine and transmission. It could be removed without affecting the overdrive transmission.

Drive-Master and overdrive exist separately. Someone obviously had Drive-Master in your car, had problems with it, and removed the power unit (which is attached to the engine and transmission), leaving only the dash switches. No great loss. But at some point, should you wish, you can collect, rebuild, and re-install the Drive-Master power unit, hook it up to your switches, and have semi-automatic three speed shifting.

You have an overdrive transmission. Celebrate this fact. You can now drive effortlessly all day at 60-65 mph (or faster if you dare). You can't really do this with a regular three-speed tranny, unless you change over your rear end gears.

The OD dash switch for the overdrive, enables you to "kick down" from overdrive (fourth gear) to third gear when passing, or needing extra power. It was originally placed by the factory under the accelerator pedal, so you merely tromped the gas pedal to the floor to kick down. Much as you do in a modern automatic transmission-equipped car. Some Hudson people place this momentary-contact switch on the dashboard, in order to spare the clutch the strain that comes with sudden kickdown. This can be a problem in more powerful Hudson engines, for it can twist the input shaft. When you have a dash-switch equipped car, your kickdown is accomplished by easing up on the accelerator, pressing the button (causing kickdown into third), then easing down on the accelerator. That's a lot to think about when you're in the passing lane and 10 tons of tractor-trailer is coming at you. It's much easier to just ''floor it''. But with a dash mounted kickdown switch, you cannot do that.

Once again, on overdrive operation: the overdrive can either be enabled, or locked out. There is a knob somewhere under your dash. When pulled out, the overdrive is locked out and your car behaves just like a three-speed. When pushed in, your overdrive is enabled for use, but is not activated. To actually go into overdrive (when the knob has been pushed in) you must be traveling at a speed of somewhere between 28-35 mph. Then, let off the gas and you hear a click. The car shifts into fourth gear. Now press the accelerator again and continue in fourth until you need to downshift (see above, on how to do this). Once you have downshifted to third, you can return to overdrive at a speed between 28-35 mph by merely letting up on the gas.

When you enable overdrive, but you have not yet activated overdrive, you will be in free-wheeling: the engine will not act as a drag on the car when you're going downhill. As soon as you shift into overdrive, it [u]will[/u] go into direct drive and the engine will slow you down on a hill. So when driving at lower speeds in hilly areas, stay in conventional 3-speed for safety.

Wow! Thats.....uhm.....that's just crazy (in a good way I suppose, I guess I'll find out when I actually get to driving the car). There were a couple of knobs under the dash which I didn't understand what they were for and didn't seem to do anything (like opening vents & such), but also didn't appear in the owners manual diagrams (at least not that I saw anywhere). So I'm guessing that is the lever you are referring to that one must push in to engage the OD.

You are right...this sounds like a lot to think about when driving! I know the guy I bought it from said it took a lot of getting used to (especially to us 30-somethings who grew up driving automatics!). Something tells me I'm going to need to print out your instructions and tape them to the dash for awhile!

You are also correct that the paraphernalia (as I refer to it) for the Drive Master is gone from under the bonnet. Looking at the complexity of it, I think I'll keep it that way....plus there's quite a cost factor in having one rebuilt and installed.

I am impressed by Hudson's mechanical ingenuity and complexity.

It will take you about 15 minutes to learn how to drive an overdrive. It becomes a mindless activity, like shifting gears. Many automotive makes had these transmissions, from the late 1930's up into the 70's or even 80's.

The OD lockout knob is mounted beneath the dash, is round and silvery, about 1-1/4" in diameter, with stamped, concentric circles on the face. Unless someone has replaced it with a non-Hudson knob.

With any luck you have a driver's manual which will go into its operation in detail.