GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Identification

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For more information concerning manual transmission identification, please refer to General Information & Maintenance of this guide.

Manual transmissions are officially identified by using the following descriptions:

  1. The number of forward gears.
  2.  
  3. The measured distance between the center lines of the mainshaft and the countergear.
  4.  

The 4-speed (77.5mm) transmission is a fully synchronized unit with blocker ring synchronizers and a sliding mesh reverse gear. It is contained in an aluminum alloy case with an integral clutch housing, a center support and an extension housing, which houses some of the gears, bearings and shafts. The shift lever is mounted on top of the extension housing. This transmission is used with the early 2.8L 6-cylinder and the 1.9L 4-cylinder engines. The easiest way to identify the 77.5mm transmission is that the gear box and bell housing are one casting.

The 4-speed (77mm) and 5-speed (77mm) model transmissions are fully synchronized units with blocker ring synchronizers and a sliding mesh reverse gear. They have the more familiar aluminum gear box type of transmission case that houses the various gears, bearings and shafts. The floor-mounted gearshift lever assembly is located on top of the extension housing. The ML2 (through 1989) model is used with 2.5L 4-cylinder engines; the ML3 (through 1991) model is used with the V6 engine. The easiest way to identify 77mm transmissions from the 77.5mm is that the gear box can be removed from the bell housing.

For 1992-93 models, the MW2 (New Venture Gear 3500) manual transmission was available for 6-cylinder engines. This transmission is similar to the 5-speed 77mm model used earlier, except that on the MW2, the bell housing-to-engine bolts must be removed in order to remove the transmission assembly from the engine.

 
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