GM Transmission Torque Specificationsby Rob Wagner
Tightening General Motors manual and automatic transmissions to the engine block requires specific twisting force with a torque wrench. The torque wrench allows the mechanic to tighten the bolts at a specific pressure called pound-feet.
Chevrolet small-block engines, produced by General Motors, include the 267-, 327- and 350-cubic-inch V8s. The torque specifications for the bellhousing that mounts the transmission to the engine block is 25 ft.-lbs. The harmonic damper's torque is 60 ft.-lbs. The clutch pressure plate is 35 ft.-lbs. The automatic transmission flexplate must be torqued to 60 ft.-lbs. The manual transmission's flywheel also must be 60 ft.-lbs.
Torque specifications differ slightly between big-bock and small-block Chevy engines and transmissions. Big-Block engines require 85 ft.-lbs. of torque pressure for the harmonic damper. The flexplate, flywheel, clutch pressure and bellhousing require the same torque specifications as the small-block versions.
Smaller GM Engines
GM transmissions matched with 3.0-liter and smaller engines require different torque specs. The 2.2-liter GM engine matched with a Borg T-5 transmission requires 55 ft.-lbs. to mount the transmission in the bellhousing. The cover plate to the transmission is 46 ft.-lbs. The transmission to the engine block on all pre-1999 cars is 66 ft.-lbs. Model year 1999 and later models require 35 ft.-lbs.