The 1987 Chevy S-10 Blazer 4x4's transmission fluid capacity depends on the type of transmission it has. There were several options available that year. You
must check your owner's manual or a reliable repair manual specific to your truck's VIN number (Vehicle Identification Number) to know for certain.
Without knowing the exact transmission, providing a specific quart amount is unreliable and could lead to improper fluid levels. Incorrect fluid levels can damage your transmission.