The American Automobile Industry in World War Two
An American Auto Industry Heritage Tribute by David D Jackson

 Overview      Lansing Michigan in World War Two   The U.S. Auto Industry at the Normandy Invasion, June 6, 1944    The U.S. Auto Industry and the B-29 Bomber   U.S. Auto Industry Army-Navy "E" Award Winners   The Complete listing of All Army-Navy "E" Award Winners   Sherman Tanks of the American Auto Industry   Tank Destroyers of the American Auto Industry    M26 Pershing Tanks of the American Auto Industry   M36 Tank Destroyers of the American Auto Industry   Serial Numbers for WWII Tanks built by the American Auto Industry   Surviving LCVP Landing Craft    WWII Landing Craft Hull Numbers   Airborne Extra-Light Jeep Photos  The American Auto Industry vs. the German V-1 in WWII   American Auto Industry-Built Anti-Aircraft Guns in WWII   VT Proximity Manufacturers of WWII   World War One Era Motor Vehicles   National Museum of Military Vehicles   Revisions   Links

 Automobile and Body Manufacturers:  American Bantam Car Company   Briggs Manufacturing Company   Checker Car Company   Chrysler Corporation   Crosley Corporation   Ford Motor Car Company   General Motors Corporation   Graham-Paige Motors Corporation   Hudson Motor Car Company   Murray Corporation of America   Nash-Kelvinator   Packard Motor Car Company      Studebaker    Willys-Overland Motors

General Motors Divisions:  AC Spark Plug   Aeroproducts   Allison   Brown-Lipe-Chapin   Buick   Cadillac   Chevrolet   Cleveland Diesel   Delco Appliance   Delco Products   Delco Radio   Delco-Remy   Detroit Diesel   Detroit Transmission   Electro-Motive   Fisher Body   Frigidaire   GM Proving Grounds   GM of Canada   GMC   GMI   Guide Lamp   Harrison Radiator   Hyatt Bearings   Inland   Moraine Products   New Departure   Oldsmobile   Packard Electric   Pontiac   Saginaw Malleable Iron   Saginaw Steering Gear   Southern California Division   Rochester Products   Ternstedt Manufacturing Division   United Motors Service   Vauxhall Motors

 Indiana Companies:  Bailey Products Corporation   Chrysler Kokomo Plant   Continental Steel Corporation  Converto Manufacturing    Cummins Engine Company   Diamond Chain and Manufacturing Company   Delta Electric Company   Durham Manufacturing Company   Farnsworth Television and Radio Corporation   General Electric Kokomo Plant   Haynes Stellite Company   Hercules Body Company   Horton Manufacturing Company   Howe Fire Apparatus   International Machine Tool Company   J.D. Adams Company   Kokomo Spring Company   Magnavox   Muncie Gear Works   Pierce Governor Company   Portland Forge and Foundry   Reliance Manufacturing Company   Republic Aviation Corporation - Indiana Division   Ross Gear and Tool Company   S.F. Bowser & Co.   Sherrill Research Corporation   Tokheim Oil Tank and Pump Company   Warner Gear   Wayne Pump Company   Wayne Works

Commercial Truck and Fire Apparatus Manufacturers:  American LaFrance   Autocar   Biederman Motors Corporation   Brockway Motor Company   Detroit General   Diamond T   Duplex Truck Company   Federal Motor Truck   Four Wheel Drive Auto Company(FWD)   International Harvester   John Bean   Mack Truck   Marmon-Herrington Company   Michigan Power Shovel Company   Oshkosh Motor Truck Corporation   Pacific Car and Foundry   "Quick-Way" Truck Shovel Company   Reo Motor Car Company  Seagrave Fire Apparatus   Sterling Motor Truck Company    Ward LaFrance Truck Corporation   White Motor Company

Aviation Companies:  Abrams Instrument Corporation   Hughes Aircraft Company   Kellett Aviation Corporation   Laister-Kauffman Aircraft Corporation   Naval Aircraft Factory   P-V Engineering Forum, Inc.    Rudolf Wurlitzer Company-DeKalb Division  Schweizer Aircraft Corporation   Sikorsky Division of United Aircraft Corporation   St. Louis Aircraft Corporation   Timm Aircraft Corporation

Other World War Two Manufacturers:  Air King Products   Allis-Chalmers   American Car and Foundry   American Locomotive   American Stove Company   Annapolis Yacht Yard   Andover Motors Company   B.F. Goodrich   Baker War Industries   Baldwin Locomotive Works   Blood Brothers Machine Company   Boyertown Auto Body Works   Briggs & Stratton   Caterpillar   Cheney Bigelow Wire Works   Centrifugal Fusing   Chris-Craft   Clark Equipment Company   Cleaver-Brooks Company   Cleveland Tractor Company   Continental Motors   Cushman Motor Works   Crocker-Wheeler   Dail Steel Products   Detroit Wax Paper Company   Detrola   Engineering & Research Corporation   Farrand Optical Company   Federal Telephone and Radio Corp.   Firestone Tire and Rubber Company   Fruehauf Trailer Company   Fuller Manufacturing   Galvin Manufacturing   Gemmer Manufacturing Company   General Railway Signal Company   Gibson Guitar   Gibson Refrigerator Company   Goodyear   Hall-Scott   Hanson Clutch and Machinery Company   Harley-Davidson   Harris-Seybold-Potter   Herreshoff Manufacturing Company   Higgins Industries    Highway Trailer   Hill Diesel Company   Holland Hitch Company   Homelite Company   Horace E. Dodge Boat and Plane Corporation   Huffman Manufacturing   Indian Motorcycle   Ingersoll Steel and Disk   John Deere   Johnson Automatics Manufacturing Company   Kimberly-Clark   Kohler Company   Kold-Hold Company   Landers, Frary & Clark  Lima Locomotive Works   Lundberg Screw Products   MacKenzie Muffler Company   Massey-Harris   Matthews Company   McCord Radiator & Mfg. Company   Metal Mouldings Corporation   Miller Printing Machinery Company   Morse Instrument Company   Motor Products Corporation   Motor Wheel Corporation   National Cash Resgister Company   Novo Engine Company   O'Keefe & Merritt Company   Olofsson Tool and Die Company   Oneida Ltd   Otis Elevator   Owens Yacht   Pressed Steel Car Company   Queen City Manufacturing Company   R.G. LeTourneau   Richardson Boat Company   R.L. Drake Company   St. Clair Rubber Company   Samson United Corporation   Shakespeare Company   Sight Feed Generator Company   Simplex Manufacturing Company   Steel Products Engineering Company   St. Louis Car Company   Twin Disc Company   Victor Adding Machine Company   Vilter Manufacturing Company   Wells-Gardner   W.L. Maxson Corporation   W.W. Boes Company   Westfield Manufacturing Company   York-Hoover Body Company   Youngstown Steel Door Company  
   

 Main Detroit Transmission Page
Detroit Transmission (Hydra-Matic) Division of General Motors Corporation in World War Two / WWII

The Detroit Transmission Torqmatic Model 900-T
- as used in the M18 Hellcat Tank Destroyer and M26 Pershing

This page added 12-27-2016.
The circa 1944 Detroit Transmission sales brochure on the Torqmatic 900-T Transmission reproduced below provides the most information that can be found on the transmission used in the Buick M18 Hellcat tank destroyer.  Publications on the M18 have had very little information, if any, on the transmission in the Hellcat.  If the publications say anything, they indicate the vehicle had a Torqmatic, Torquematic, or fluid coupled transmission.  That is all.

While the engine, armor and armament are all discussed in detail in various books on the vehicle, only one or two words are used to describe the transmission.  The reader is then left wondering what the Torqmatic or fluid coupled transmission was.  And who built the transmission?  That key piece of information was missing until in March 2016 when I posted the1944 Detroit Transmission booklet "Teamwork in Peace and War."  For the first time in print, the Torqmatic is described in detail.

The information provided in "Teamwork in Peace and War" is a huge step forward in understanding the WWII Torqmatic.  The Torqmatic 900-T sales brochure now opens up the transmission and gives the details on how it works internally.  While now, 70 years later, automatic transmissions are standard equipment and their operation understood, that was not the case in 1944.  This concept was all new at the time, especially to military leaders who by nature are conservative in their thinking, think they know it all, and do not want to change, even though there is a better way of doing something.

The "Torqmatic 900-T" brochure is filled with detail on how it worked.  It is a treasure trove of information for the military hardware historian and enthusiast.

While not explicit,  the document indicates that the 900-T was the transmission used in the M18 Hellcat.  On page 4, the graph shows tractive effort vs. speed for the T70 tank destroyer, which later was redesigned as the M18.  Other implicit details in the brochure are that the top speed which matches with the top speed of the M18, along with the torque and horsepower rating of the Continental R-975 400 hp radial engine used in the M18.

It would appear from the brochure that Detroit Transmission was attempting to have the 900-T fitted in an M4 tank, as there are several pictures of it. 

Technically there is the general description, performance characteristic, operation, construction, torque converter, cooling circuit, hydraulic systems, and applications along with multiple engineering drawings of the Torqmatic 900-T.  This is as complete a description as one can hope to find on this rare WWII tank destroyer transmission. 

  
 This M18 Hellcat is at Ropkey Armor Museum in Crawfordsville, IN.  Author's photo added 12-27-2016.

  
Looking through the driver's hatch the Detroit Transmission Division of GM Torqmatic automatic transmission is viewable.  The Buick M18 was the only tank destroyer to have an automatic transmission.  Author's photo added 12-27-2016.


Here the gearshift handle is viewable along with the gear indication on top of the transmission.  On the floor there are only the accelerator and brake pedals.  A clutch pedal is not needed with the automatic transmission.  Author's photo added 12-27-2016.


Author's photo added 12-27-2016.

"The Torqmatic Transmission Model 900-T"
General description, performance characteristic, operation, construction, torque converter, cooling circuit, and hydraulic systems

For the WWII tank enthusiast, there is a treasure trove of information on the transmission used in the M-18 Hellcat.  Much of the information is also generic to the Torqmatic transmission used in the T26/M26 Pershing.



General Description of the Detroit Transmission Torqmatic 900-T


The Torqmatic 900-T weighs 1,200 lbs.  The only operation the driver had to do with the 900-T was set the range.  There was no clutch pedal to operate.

Performance of the Detroit Transmission Torqmatic 900-T


This graph is of tractive effort of the Torqmatic 900-T with the T-70 Tank Destroyer, which became the M-18 Hellcat.  This graph therefore ties the 900-T to the M-18 and is the only evidence of what model Torqmatic was installed in the vehicle.  With this key piece of information, the rest of the data in the booklet provides more detail on the M-18's transmission.


Once the speed range was set, the M-18 could be driven at any speed from 0 mph to the top speed of the range without the changing gears or use of a clutch by the driver. 
Low Range:  0 to 16 mph
Intermediate Range:  0 to 34 mph
High Range:  0 to 60 mph

Operation of the Detroit Transmission Torqmatic 900-T


While the performance section indicated that the M-18 could be operated from 0 to the maximum range of the any of the three forward ranges under light loads, this page indicates that under full load there are restrictions.  For the intermediate range the M-18 should be operated at 11 to 34 mph and in the high range at the speed of 30 to 60 mph.



General Construction of the Detroit Transmission Torqmatic 900-T


The key point on this page is that when shifting ranges there is no loss of power flow.  This means the tank would not slow down or stop as would tanks with clutches.  This was very important on the battlefield.

The Torque Converter of the Detroit Transmission Torqmatic 900-T

The Cooling Circuit of the Detroit Transmission Torqmatic 900-T



The Hydraulic System of the Detroit Transmission Torqmatic 900-T

Applications for the Detroit Transmission Torqmatic 900-T


Only the M-18 and the M-26 utilized Torqmatic Transmissions during WWII.  But the technical advantages outlined in this brochure have been used on every American tank built after WWII.  General Motors transferred the technology to the Allison Division in Indianapolis in 1946 as the CD-850 series.  Today Torqmatic is a trade name for transmission built by Allison Transmission.

 

 

 

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