Gear ratio in rear end of 1989 Chevy Halfton 4x4?

There's no single answer to the rear end gear ratio in a 1989 Chevy Half-ton 4x4. The ratio varied depending on the options chosen when the truck was new (engine size, transmission type, intended use, etc.). To find the gear ratio for *your* specific truck, you need to check one of the following:

* The vehicle's data plate (usually located on the driver's side doorjamb): This might list the axle ratio.

* The decal on the differential cover (if still present): This is the most straightforward method. The ratio will be printed directly on the sticker.

* The owner's manual (if you have it): This may list the axle ratio as a specification.

* Physically inspect the differential: You can do this by removing the cover (requiring tools and some mechanical aptitude), counting the teeth on the ring gear and pinion gear, and calculating the ratio. This is more involved and requires knowledge of differential operation.

Without access to one of those sources, determining the gear ratio for your specific 1989 Chevy Half-ton 4x4 is impossible.