The early days of any new technology are always the most diverse and interesting, as so many different approaches are tried to achieve the same goal. This was particularly the case with automatic transmissions; there were a dizzying array of different engineering solutions to rid Americans of the task of shifting their balky transmissions. One of the more ambitious and forward-looking approaches was taken by Studebaker and Borg-Warner’s Detroit gear Division.
Borg-Warner was by far the largest transmission supplier in the industry, so it was only natural that they also began developing automatic transmission designs. BW had taken an important step in that direction back in 1934 with the first mass-produced overdrive unit, which allowed some clutch-free shifts and “automatic” shifts in and out of overdrive (full story here).
Studebaker and BW’s Detroit Gear Division (“DG”) collaborated on a fully-automatic transmission for some time. Presumably, BW did the heavy lifting, as their experience was much deeper than Studebaker, which bought all of their manual transmissions from BW. But undoubtedly, Studebaker had certain qualities that they wanted to see in the new automatic, the most important one being more efficient and economical than the typical one-speed torque converter units recently deployed by Buick (Dynaflow) and Chevrolet (Powerglide).
Introduced mid-year in the 1950 model year as an expensive $201 option ($2000 adjusted), the key difference was that the BW DG Automatic Drive (“DG”) had a clutch to lock up the torque converter, essentially turning the unit into a mechanical direct-drive in high gear. The unit had three bands and two planetary gear sets, yielding two forward gears in the conventional sense, inasmuch as high (third gear) was completely direct.
The DG would start in intermediate gear (2nd), which had a 1.4:1 gear ratio. Combined with the torque converter’s 2.0:1 effective gear ratio, starting gear multiplication was 3.08:1. That compares to 2.1:1 for the early Powerglide, which started in direct gear, and thus the DG gave relatively better acceleration. Depending on throttle position, the upshift into direct drive occurred between 18 and 58 mph.
Here’s a more detailed description from a 1950 Popular Science article:
One criticism often voiced against automatic transmissions is that they
deprive the driver of choice. That this isn’t true of the Studebaker/Borg-
Warner drive is shown by the following description of what happens when the
selector lever is in the drive position. It’s also eloquent proof that
motorists must understand their transmissions to get the most out of them.
At the moment of starting, with the selector lever at “D,” the power
train is through the torque converter and intermediate gear. Starting
torque ratio in the transmission (not counting the advantage of rear-axle
ratio) is 3.08 to 1, or more than three turns of the engine crankshaft for
every turn of the propeller shaft. Automatic shifts from intermediate gear
to direct drive occur within the following limits, depending on speed,
throttle position and load:
1. Starting with a very light accelerator depression, the transmission
shifts from intermediate to direct at about 18 mph.
2. Starting with full throttle (not depressed past the kick-down abutment
on the floor-board), the transmission shifts into direct at about 35
3. Staring with any accelerator depression between between light and full
throttle, the transmission shifts into direct between 18 and 35 mph, depending
on accelerator position.
4. Starting with full throttle and accelerator depressed past the kick-
down point, the shift into direct drive occurs at about 58 mph.
5. Coasting in direct with accelerator released, the transmission downshifts
into intermediate gear plus converter at 12 mph.
6. Direct drive may be over-ruled to provide added torque available in
intermediate by depressing the throttle to the kick-down point at any
speed below 50 mph.”
One wonders whether these cars felt rather sluggish, when shifting into locked mechanical direct drive as low as 18 mph? It’s the same as shifting into third in a manual at that speed. And apparently, the shift from intermediate (with torque converter) into Direct Drive was never a very subtle transition, and could become a bit abrupt if the transmission was not working ideally.
Low gear could be employed manually for climbing or descending steep hills, or for a quicker getaway from start, with a manual upshift required to Drive. Generally, that was not encouraged to be done regularly on these early automatic transmissions as the bands were not designed for repeated use this way. And the shift was never smooth.
The high mechanical efficiency and resulting fuel economy of direct drive was of particular appeal to Studebaker, as it prided itself on its smaller, lighter and more efficient cars. Tests yielded over 20 mpg, depending on engine and driving style. In a 1951 Commander with the new 120 hp OHV V8, tested by three magazines, the average 0-60 time was 17.0 seconds, about 4-5 seconds more than with a manual transmission. 1/4 mile times averaged at 20.8 seconds, top speed 95.9 mph, and fuel economy 22.3 mpg, a very good number considering the times, and for a V8 powered sedan.
Another feature of the Automatic Drive was the Anti-Creep Hill Holder, a solenoid-operated valve that kept brake pressure in the rear brakes after a stop until the gas pedal was depressed. It’s a bit hard to see the benefits in an automatic unlike in a manual transmission.
It should be pointed out that the DG automatic was not the only one with a locking torque converter to effect direct drive. Packard’s Ultramatic also employed a clutch, but only had one normally-used “gear”, like the Buick Dynaflow and early Powerglide. Later units did start in Low, as well as other refinements.
Ford, which was woefully behind in automatic transmission development, asked to purchase and/or also build the DG automatic, which had the potential to lower unit costs for Studebaker. But Studebaker President harold Vance insisted on at least a one-year exclusivity, so Ford went to Borg Warner Warner Gear Division (not their Detroit Gear Division) and bought what became the Ford-O-Matic, production volume to be 50% by Ford, 50% by BW.
This was a somewhat more conventional automatic, with a torque converter and a Ravigneaux planetary gearset allowing three forward gears, although Low was not automatically engaged when starting off. The Fordomatic was the first torque converter automatic to shift without an interruption of its power flow though its torque converter. As such, it was the beginning of two long lines of transmissions: the Ford MX/FX/MFX (Cruise-O-Matic), which was basically a Fordomatic that started in Low (along with other improvements), and BW’s own line of automatics, including the Model 35 transmission, used extensively by AMC and numerous European and Japanese automakers.
Not surprisingly, there were a number of similarities between the DG and the Fordomatic, but the Fordomatic was clearly more pragmatic and cheaper to build.
In 1953, Chevrolet’s Powerglide was reworked considerably, and now started in Low, automatically, which yielded an effective gear ratio of 3.82:1, substantially better than the DG 3.08:1.
This effectively turned the DG into a three-speed automatic, the first with a torque converter (GM’s four-speed Hydramatic used a fluid coupling), and with a locking one at that.
For two brief years (1954-1955), Studebaker’s automatic was the most advanced and most efficient in the land. But it ended all-too soon.
Studebaker sales swooned in 1955. BW demanded a substantial price hike for their complex DG transmission, due to the low volumes. Studebaker decided to buy BW’s other automatic, essentially the Fordomatic, now dubbed Flight-O-Matic.
Curiously, some of the Flight-O-Matics started in Low, others not. The initial 1956 version used on the V8 Commander did, but that was changed mid-year. Apparently the shift from Low to 2nd was not smooth enough, and Low gear was noisy. And typically, these transmissions shifted from Low to 2nd very soon, like around 7-8 mph, thus not fully utilizing the engine’s power band.
By 1957, there were two versions of the Flight-O-Matic; the V8 version started in 2nd, but the lighter six cylinder version started in Low. The issue of modifying these transmissions to give a start in Low, or hold low until 25-30 mph, is one of on-going interest to Studebaker enthusiasts, as this forum page attests.
The DG didn’t end with Studebaker in 1955. Tooling was sent to England, were it was built and used in Jaguars for a number of years. There was even a modification, an upshift retarder, to keep it from shifting into Direct Drive too soon, which rather spoiled the already-dulled performance of the XK engine further.
It was also used by other European makes, including Mercedes, for their 300 sedan. I had always wondered what they used in that, as they did not have an automatic of their own at the time. Given the Mercedes-Studebaker connection (Studebaker-Packard was the US Mercedes distributor), that makes a rather fitting solution. The transmission Studebaker could no longer afford ends up in their luxury import. And makes servicing it at Studebaker dealers readily possible. What goes around, comes around. Or gets locked up, in the case of the DG’s torque converter.
More on vintage transmissions: