Rebuild your Allison 1000- or 2000-series transmission with this easy-to-follow book that features step-by-step procedures. Introduced in 1999 by Allison and 2001 by General Motors, the Allison 1000- and 2000-series transmissions have become the most popular heavy-duty transmissions in production today. Used by multiple manufacturers, including GM, Freightliner, International, etc., millions are on roads around the world. Automatic transmissions are often seen as mysterious and overly complicated, but much of the guesswork has been simplified to its basic elements in this easy-to-follow guide. This book covers the identification process, operation, diagnostic pointers, common failures, and repair and rebuild procedures for the 1000- and 2000-series transmissions. Upgrades to make the 1000 more robust for performance applications are covered as well as the companies that offer upgrades. This detailed instructional manual is authored by Steve Garrett, a service engineer and instructor for General Motors and a member of the Automatic Transmission Rebuilders Association (ATRA). Quality photos of the rebuild process are featured along with torque specifications and identification of all major and most minor components. If you are looking at performing a rebuild project on your own or you just want to know how your Allison works, this is the book for you.