USA Standard Axle For GM 8.2in & 8.5in Passenger Car. 29 1/2in Long / 28 Spline / 2.780in Hub

28-Spline GM 8.2in and 8.5in Rear Axle Shaft for Early Camaro, Chevelle, and Firebird Applications

The ZA G1255803-SH from USA Standard Gear is a precision replacement rear axle shaft for General Motors 8.2in and 8.5in semi-floating rear axle applications found in a wide range of classic GM muscle cars and pony cars. Measuring 29 1/2 inches in length with a 28-spline count and a 2.780-inch brake pilot, this shaft is designed as a direct-fit replacement for early Chevelle, first-generation Camaro, and Firebird applications. Produced from 1541H alloy steel, the ZA G1255803-SH provides the strength and fatigue resistance appropriate for street-driven classic cars and those used in spirited performance driving.

This shaft fits applications on the GM 8.2in or GM 8.5in rear axle housing where this specific 29 1/2-inch, 28-spline shaft is required. This shorter length compared to similar GM shafts makes it specific to a subset of classic car fitments, so confirming the length against your original shaft is essential before installation. USA Standard Gear backs the ZA G1255803-SH with a 10-year limited warranty against manufacturer defects.

What's Included

• 1 x USA Standard Gear ZA G1255803-SH Rear Axle Shaft

Specifications

Vehicle Fitment

About USA Standard Gear and the GM Classic Car Market

USA Standard Gear, a brand under Yukon Gear and Axle, has built a strong reputation in the classic car restoration and performance upgrade market by producing drivetrain parts that match the original equipment specifications of vintage GM platforms. The GM 8.2in and 8.5in rear axles are among the most common differentials found in classic muscle cars, and maintaining an accurate parts supply for these axles is essential for keeping these vehicles on the road. This shaft reflects the brand's commitment to providing correct-fit replacement components for these important classic platforms.

Frequently Asked Questions

What vehicles does this shaft fit?
This shaft fits 1965 through 1972 Chevrolet Chevelle, 1967 through 1969 Chevrolet Camaro, and 1970 through 1981 Pontiac Firebird vehicles equipped with the GM 8.2in or GM 8.5in semi-floating rear axle where the 29 1/2-inch shaft length applies.

What is the difference between this shaft and the ZA G1255802-SH?
Both shafts share the same 28-spline count and 2.780-inch brake pilot, but differ in length. The ZA G1255803-SH is 29 1/2 inches long, while the ZA G1255802-SH is 30 1/8 inches long. The correct part depends on which side and which specific vehicle application you are working on. Always measure the original shaft before ordering.

How do I confirm whether my classic Camaro needs this shaft or a different one?
The best method is to measure the length of the shaft being replaced from end to end. If the measurement is 29 1/2 inches and the spline count is 28, this is the correct replacement. Also verify the brake pilot diameter of 2.780 inches.

Does this shaft fit both the GM 8.2in and the GM 8.5in axle?
Yes. This shaft is dimensioned to fit both the GM 8.2in and GM 8.5in semi-floating rear axle housings in the listed applications. Confirm spline count and length match before installation.

What material is this shaft made from?
The shaft is produced from 1541H alloy steel. The elevated manganese content in this alloy improves case hardening depth and fatigue life, which is why it is a preferred material for performance and OEM-replacement axle shafts.

Will this shaft work with a Positraction carrier in a Camaro or Firebird?
Yes. The shaft engages with the carrier side gear, and the limited-slip function of the carrier is independent of the shaft itself. As long as the 28-spline specification matches your carrier's side gear, this shaft is compatible with both open and limited-slip carriers.

What warranty does this shaft carry?
USA Standard Gear backs the ZA G1255803-SH with a 10-year limited warranty against manufacturer defects. This warranty is offered in compliance with the Magnuson-Moss Warranty Act. Retain your purchase documentation for warranty service.

Is this shaft suitable for a first-generation Camaro restoration?
Yes. This shaft covers first-generation Camaro years 1967, 1968, and 1969 where the GM 8.2in or GM 8.5in rear axle was used with this shaft length. It provides an OEM-correct replacement shaft for a restoration build.

Can this shaft be used on a 1965 Chevelle in a drag racing application?
This is a quality street-grade replacement shaft. For vehicles subjected to high launch forces at the drag strip, evaluate whether a heavy-duty or chromoly-grade axle shaft better matches the power level and usage demands of the application.

Installation Instructions

1. Raise the vehicle safely and support it on rated jack stands. Remove the wheel on the side being serviced.
2. Remove the brake drum or disc brake components as appropriate for your application.
3. Remove the differential cover and drain the gear oil completely.
4. Remove the pinion shaft retaining bolt and withdraw the pinion shaft from the carrier.
5. Push the axle shaft inward to access the C-clip groove, then remove the C-clip.
6. Slide the old axle shaft out of the housing tube. Inspect the axle seal and bearing for wear; replace any damaged components before proceeding.
7. Insert the ZA G1255803-SH into the axle tube, engaging the splines with the carrier side gear. Push inward until the C-clip groove is accessible inside the differential.
8. Install the C-clip in the groove, then pull the shaft outward to fully seat the C-clip against the side gear face.
9. Reinstall the pinion shaft and torque the retaining bolt to the manufacturer's specification.
10. Clean the differential cover sealing surface thoroughly. Reinstall with a new gasket or appropriate RTV sealant and torque the cover bolts evenly.
11. Fill the differential with the correct gear oil type and quantity.
12. Reinstall brakes and wheel. Torque all fasteners to specification.
13. Lower the vehicle and test drive. Inspect for gear oil leaks after the test drive.