The blue cover THM-400, 3L80 ATSG overhaul manual covers procedures and technical service information for transmission inspection, repair, dis-assembly, assembly, diagnosis, and troubleshooting.

This book contains detailed information regarding the following:

Bushing locations
Checkball locations
Clutch clearance specifications
Endplay check and recommendations
Exploded views
Line pressure check procedures and specs
Recommended tools list – Not all required
Thrust washer locations
Torque specifications
Torrington bearing locations
Trouble shooting
Valve body assembly detail for valves and springs
Much more….
The TH400 and its variants were in production from 1964-1992 and can be identified by the irregular shaped, 13 bolt oil pan and 3 forward gears.

The TH400 was found in the full range of General Motors and other brand vehicles including, GM, Buick, Cadillac, Chevrolet, GMC, Jaguar, Jeep, Oldsmobile, Pontiac, and Rolls Royce.

This transmission is part of the Turbo-Hydramatic series and also known by the following codes and model numbers: TH400, TH-400, 3L80, TH475, THM375, M40, THM400, THM-400, 3L80HD

Automatic Transmission Service Group (ATSG) is the largest technical support service in the automatic transmission Industry. ATSG manuals are the world's foremost service guides utilized by professionals and technicians to troubleshoot and diagnose problematic areas, disassemble transmissions and reassemble accurately and efficiently. ATSG manuals cover all aspects of transmission care, overhaul and rebuild procedures. Straightforward and simple to use, ATSG manuals will assist professionals and non-professionals alike with all aspects of automotive transmission care.