Overdrive versus High Speed Gears?

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The recent posts on Phil Bray’s high speed gears and the number of people who are using them make me wonder if anyone has gone the other route and has installed an overdrive instead.

I have a Mitchell overdrive on a 1926 Packard Eight Phaeton and think it’s great. In my hilly country near southern Vermont, it preserves the original gear ratios when needed but give me a much appreciated fourth-gear for cruising.

If you are using an overdrive, which make is it? Where is it installed — middle, transmission-side, near the axle? Any comments?

Thanks — Scott

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PAS member Lloyd Young in Ohio can add an electrically controlled Borg-Warner O/D unit at the back that is very reliable and inexpensive. Pierce went to the Borg-Warner starting in 1936 but had centrifugal control. Putting one of these units in a 1932 would also be an option. I’ve got both types in different cars and much prefer the electronic solenoid version. The change with the B/W is about a 20% RPM reduction and it retains all of the original ratios along with the high speed option. In my opinion the only down side as compared to a gear ratio change is the judging point deduction.

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I’ve been thinking along these same lines.

Our ’34 Buick has a 4.88:1 rear-end ratio which is great for the hilly parts of our tours, but tops-out when approaching cruising speeds. The addition of a 30% Borg-Warner overdrive effectively gives me a comfortable cruising speed without worry over the long-stroke, high-rpm effect on rod bearings.

With a 30% reduction in engine speed, if we were driving at 60mph the engine would be running as if we were driving at 42mph

Another major benefit of the overdrive is that I can drive the car as if it were a 5-speed transmission. Of course this rarely happens, but the capability is there.

Since the Buick was a torque-tube drive shaft, the tube had to be cut and modified. The work was performed “flawlessly” by Lloyd Young of Canal-Winchester, Ohio, probably in 2003 or 2004. He also installed the same type overdrive system in the 1912 Oakland we drove on many tour, making the car much more driveable. Previously there were times when 2nd gear was too low and 3rd gear was too high — 2nd overdrive solves that !

Installation is at the rear axle.

I’m considering the same arrangement on our ’30 Packard, but may also look at the GEARVENDORS overdrive, a newly-manufactured unit, as opposed to an 80 year old Borg-Warner unit.

Has anyone else gone this route?

Marty Roth

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Hi Scott,

I love the Columbia overdive (OEM 2-speed rear end) in my 1947 Ford. I actually got 20 mpg on one trip, cruising at 60. That said, I would like to hear from any PAS members who have installed overdrives on their 1933-1935 Pierces (with Stewart-Warner power brakes).

Bob Jacobsen

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I have had installed, but not yet driven, a Gear Vendors unit in my 1932 Model 54 eight cylinder Club Sedan. It cost $3000 (gulp), and of course the considerable installation labor was additional. Some of the pluses and minuses (some already mentioned by others) that I see for gear-set and Gear Vendor overdrive units are:

Gear-set

Looks original – provides what some would say is a more useable first gear – is a “new” unit – provides an excellent opportunity to inspect and replace the rear end and rear axle bearings – when successful, is cheaper and easier to install than a Gear Vendors overdrive – provides engine braking without going through an additional clutch. Phil Hill unit does require some grinding of the housing.

Gear Vendors Overdrive

New, very strong, and yet light weight units – leaves all your original ratios intact, but adds two more (second overdrive and third overdrive – first overdrive is not useable – the second overdrive is what is called gear splitting) – is actuated electronically at any speed over 20 mph by the driver and is engaged hydraulically. Using it only results in about one quarter of one percent inefficiency (some other overdrive units result in much more). If my memory is right (better check!), one can get a 1.22, a 1.25, or a 1.28 ratio GV tech phone service is very good. There are also what in my thinking are significant disadvantages compared to a gear-set and some other overdrives. I wanted to keep my original transmission because I want my car to feel like an original Pierce-Arrow, so there was not room to mount the GV unit onto the transmission itself, which in my opinion would have been the simplest and most desirable approach. So we had to use what Gear Vendors calls a “remote” installation. From the rear of the transmission, first comes a universal joint, then the shortened drive shaft, then another universal joint, then the GV unit, then a third universal joint, and finally the yoke attached to the pinion gear. Unfortunately, the original positioning of the torque arm is not far enough off-center to clear the GV unit. So the torque arm was moved farther to the side, a mirror image torque arm was constructed, and the GV unit was set between the two. Luckily for me, one of the mechanics doing the installation is also a machinist. Other than costly installation, another disadvantage is that I can only use the GV unit over about 20 mph. I would have much preferred an overdrive that I could use at any speed, but due to what GV calls the unit’s hydraulic requirements, this can’t happen. Also due to the hydraulic requirements, it is not recommended to use second over for engine braking or deceleration; second or third gear is recommended for this. I haven’t given thought to how freewheeling fits into the discussion. After all this, I sure hope the xxxx thing works good!

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