SOCIETY OFAUTOMOTIVE ENGINEERS, INC. 400Commonwealth Drive, Warrendale, Pa. 15096 The New X1100 Automatic Transmissions forthe XM1 Tank J.W.Schmidt and G.L.Hadley Detroit Diesel Allison Division ofGeneral Motors Corporation International Automotive Engineering Congress andExposition Cobo Hall, Detroit February 28-March 4,1977770339 Downloaded from SAE International by University of Birmingham, Monday, August 20, 2018Copyright ©Society ofAutomotive Engineers, Inc.1977 Allrights reserved. Downloaded from SAE International by University of Birmingham, Monday, August 20, 2018770339 The New X1100 Automatic Transmissions forthe XM1 Tank J.W.Schmidt and G.L.Hadley Detroit Diesel Allison Division ofGeneral Motors Corporation THE DESIGN AND DEVELOPMENT ofthe firstpower shift transmission formilitary tracklay ingvehicles, theCD850, was begun byDetroit Diesel Allison in1946. Used initially intheM47 medium tank, ithasbeen developed further foruse intheM48 andtheM60 tanks. Other production military transmissions inthis"family" were the XT1410 fortheM88 Recovery Vehicle, theXTG411 fortheM109 andMIlO Self-Propelled Guns, the XTG250 fortheM551 Reconnaissance Vehicle, and the GS 100steer unit forthe M114 and M116 Vehicles (seeFigure 1).TheXT1410, CD850, and XTG411 transmissions arestillinproduction. Although these transmissions areoneofthemost reliable major components intheir vehicle systems, itbecame apparent inthemid-1960's that they would notmeet theArmy's requirements forfuture vehicles. TheArmy's requirements forvehicles in ABSTRACT TheX1100 isafully automatic shifting transmis sion which hasbeen designed and developed for vehicles inthe 49to60tonclass, operating at speeds of40to50mph. Amodular design isutilized toprovide application flexibility fordiesel ortur bine engines of1300 to1500 GHP, aswellasadaption tothecurrent M60 vehicle. This automatic transmission features ahydrostatic steer system with pivot steer, afourspeed range pack, integral power brakes andahigh speed reverse. Thetorque converter canbelocked upinallgear ranges to provide optimum transmission performance. Downloaded from SAE International by University of Birmingham, Monday, August 20, 20182 the 1980's and 1990's are: •Higher vehicle speeds •Improved mobility •Higher power-to-weight ratios •Compatibility with gasturbine and diesel engines •Improved steering andbraking Concept studies and design work wasbegun to meet these challenges. A"second generation" of transmissions was developed toperform with engines from 160to1500horsepower forinstallation invehicles ranging from 7to60tons. Thefollowing transmissions were developed: theX200, forthe Scout andM113 vehicles; theX300 fortheMICV and M109 vehicles; andtheX1100, for theXM1 andM60 product-improved tanks, (seeFigure 2.) Alltransmissions inthis"family" incorporate the following improvements over thefirst generation transmissions. •Fully automatic shifting •Four speeds optimized forhigh speed perfor mance •Hydrostatic steering •Integral power brakes •High speed reverse AUX-series transmissions aresimilar inopera tion; however, thispaper isdevoted tothelargest of these transmissions, theX1100. DESIGN CONSIDERATIONS In1972, before theXM1 tank designs were es tablished, efforts were begun onthe X1100 transmission under thetechnical supervision ofthe United States Army Tank Automotive Research and Development Command (TARADCOM). Guidelines were provided bytheXM1 task force at Ft.Knox viatheir Material Needs Document. Thedesign objectives oftheX1100 areasfollows: •Diesel and/or turbine engine compatability •1300 to1500 gross horsepower capacity •49to58tonvehicle weight installation •40to50MPH vehicle speed ability •16-20 ft/sec2 brake deceleration performance •Hydrostatic steer system, with pivot steer capability •High speed reverse capability •M60 vehicle adaptability •High reliability anddurability demonstrated Designing theX1100 foruseinthediesel andgas turbine versions oftheXM1, aswell aspotential usage inanM60 Product I