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How to Disassemble an Eaton Gov-Lock Differential

by Eric Strauss

The Eaton G80 Locking Differential, known as the Gov-Lock, is part of the rear axle in certain General Motors pickup trucks with solid axles. The term Gov-Lock is not an official name, but a kind of unofficial nickname that has gained popularity in the auto repair community. This differential affects the traction and torque by refining the rate at which the rear wheels turn. Sometimes truck owners may have to disassemble the differential to make repairs or replace parts.

Remove the Differential

1

Jack up the truck for access to the rear axle, then unbolt the differential cover located at the center of the axle, facing the rear of the truck, with a 13-millimeter socket. Gear lube may pour out, so be prepared with a pan or bucket to catch any spillage.

2

Use your hands to twist the drive shaft, which is connected to the axle, either direction until the restraining bolt for the G80 differential's carrier becomes visible -- in the center of the space that was enclosed by the differential cover. Then use an 8-millimeter, six-point socket to loosen the restraining bolt. This will allow you to remove the alignment shaft.

3

Push each axle hub toward the center of the truck, so they move about 1/4 inch. Then go back to the middle of the axle and rotate the differential carrier until you see the thrust block in the center of the carrier and the small C-clips on either side. Remove the C-clips using a small magnet to "pull" them from the carrier, if you cannot reach them with your fingers.

4

Pull the axle hubs out of the wheels about 12 inches. Some more gear lube may drain out, so be prepared.

5

Remove the bearing caps from the left-hand side of the differential (as you face the rear of the truck), using an 18-millimeter socket. One cap should be at the top of the assembly and one at the bottom. Note the placement, as they will need to be reinserted on the same side and with the same orientation. Pull out the differential carrier, being careful that it does not fall.

Disassemble the Differential

1

Remove the governor parts, the two small pieces that regulate the differential, by pushing a punch tool through the two holes visible in the left side of the carrier.

2

Twist either one of the assembly's side gears either direction with your hands. This rotation of the side gear will push the smaller spider gears out of the assembly.

3

Remove one side gear, then the clutch plates and side thrust washer from that side, by pulling them off the assembly with your hands -- either one piece at a time or in one large group, if possible. Then remove the other side gear and the clutch plates and side thrust washer from that side.

Tip

  • If you are looking for parts, the actual name of the G80 is the Eaton Automatic Locking Differential.

Warning

  • Always exercise proper caution and safety techniques when working on vehicles.

Items you will need

About the Author

Eric Strauss spent 12 years as a newspaper copy editor, eventually serving as a deputy business editor at "The Star-Ledger" in New Jersey before transitioning into academic communications. His byline has appeared in several newspapers and websites. Strauss holds a B.A. in creative writing/professional writing and recently earned an M.A. in English literature.

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