SAE TECHNICAL PAPER SERIES 961767 New Transmissions for Off-Highway Dump Trucks Robert L.Crum andJohn R.Wiley General Motors Corp. Reprinted from: Transmission andControls (SP-1191) International Off-Highway &Powerplant Congress &Exposition Indianapolis, IndianaAugust 26-8, 1996 400Commonwealth Drive, Warrendale, PA15096-0001 U.S.A. Tel:(412)776-4841 Fax:(412)776-5760 Downloaded from SAE International by University of Michigan, Sunday, August 12, 2018Theappearance oftheISSN code atthebottom ofthispage indicates SAE's consent thatcopies ofthepaper maybemade forpersonal orinternal useofspecific clients. Thisconsent isgiven onthecondition however, thatthecopier paya$7.00 perarticle copy feethrough theCopyright Clearance Center, Inc.Operations Center, 222 Rosewood Drive, Danvers, MA01923 forcopying beyond thatpermitted bySections 107or108ofU.S. Copyright Law. Thisconsent does notextend toother kinds of copying such ascopying forgeneral distribution, foradvertising orpromotional purposes, forcreating newcollective works, orforresale. SAE routinely stocks printed papers foraperiod ofthree years following date of publication. Direct your orders toSAE Customer Sales and Satisfaction Department. Quantity reprint rates canbeobtained from theCustomer Sales andSatisfaction Department. Torequest permission toreprint atechnical paper orpermission tousecopyrighted SAE publications inother works, contact theSAE Publications Group. Nopartofthispublication maybereproduced inanyform, inanelectronic retrieval system orotherwise, without theprior written permission ofthepublisher. ISSN 0148-7191 Copyright 1996 Society ofAutomotive Engineers, Inc. Positions andopinions advanced inthispaper arethose oftheauthor(s) andnot necessarily those ofSAE. Theauthor issolely responsible forthecontent ofthe paper. Aprocess isavailable bywhich discussions willbeprinted withthepaper if itispublished inSAETransactions. Forpermission topublish thispaper infullorin part, contact theSAE Publications Group. Persons wishing tosubmit papers tobeconsidered forpresentation orpublication through SAE should send the manuscript ora300word abstract ofaproposed manuscript to:Secretary, Engineering Meetings Board, SAE. Printed inUSA 96-0049 Downloaded from SAE International by University of Michigan, Sunday, August 12, 2018961767 New Transmissions forOff-Highway Dump Trucks Robert L.Crum andJohn R.Wiley General Motors Corp. Copyright 1996 Society ofAutomotive Engineers, Inc. ABSTRACT The new Allison M6600 and M9600 transmissions incorporate continuous improvement items toachieve greater robustness interms ofreliability anddurability. This was partially accomplished byincorporating components from higher -capacity transmissions into current products with minimal redesign andtooling. A key lifefactor foralltransmission components is adequate lubrication andcooling, andimprovements in thisarea were accomplished bydecreasing restrictions andbetter utilization ofoilthatwaspreviously exhausted tosump. The new transmission models have further enhancements toclutch lifethrough improved control of clutch torque and slip times. These clutch improvements were developed through theuse of improved computerized evaluation techniques utilizing lap-top computer programs. Also, atransmission - mounted floating-caliper, disc type park brake with integrated controls isbeing evaluated asapossible replacement forthecurrent drum-type brake. INTRODUCTION Over thirty years ago, Allison began developing and producing off-highway transmissions. To remain competitive and meet increasing needs ofthe marketplace, improvements have been made ona regular basis. Many transmission changes over the years have been driven byatrend ofincreasing weight andpower invehicle designs. Asecond major driver for transmission changes hasbeen thedesire toimprove driver comfort, specifically inthearea ofshift quality. Other significant factors that play arole inupgrading transmissions aretheavailability ofnew technology, esp