* Axle width: Measure the distance between the wheel mounting flanges. This is crucial. Different years and even models within the S-10/Blazer line used slightly different widths.
* Axle ratio: This is the gear ratio (e.g., 3.73, 4.10, 4.56). This affects your vehicle's acceleration and fuel economy. You'll want a similar ratio to maintain proper drivetrain balance. The ratio is usually stamped on the differential housing.
* Bolt pattern: The pattern of the wheel mounting bolts. This must match your existing wheels.
* Spring perch locations: The location of the spring perches on the axle housing needs to match your truck's leaf spring setup.
* Brake type: Ensure the rear end's brake setup is compatible with your existing brake lines and calipers. This could be drum or disc brakes.
Finding a compatible rear end:
1. Identify your existing axle: Look for markings on the differential housing. This will give you the best starting point.
2. S-10/Jimmy/Blazer rear ends: Many rear ends from other S-10, GMC Jimmy, and Chevy Blazer 4x4 models from similar years (late 80s/early 90s) *might* be compatible, but you must verify the specifications listed above. A slight variation in width can create significant problems.
3. Other GM trucks: Some other GM trucks from this era *might* share compatible rear ends, but the chances of direct fit are lower.
Important Note: Simply because a rear end *looks* the same doesn't mean it is. Improperly matched rear axles can cause serious drivetrain issues, binding, premature wear, and potential damage to other components. Always verify the above dimensions. If you're unsure, consult a parts professional or a mechanic specializing in S-10s/Blazers. They can help you identify the right replacement.
