[72SB]

30 spline

GM 12 BOLT SPECS
Applications:

1964 - 1982 Chevrolet & GMC 1/2 ton to 3/4 ton trucks

Full/Semi Float:

Semi floating rear axle

Ring Gear:

8.875"

Axle Spline Count:

30 spline

Axle Tube Diameter:

3.00"

Pinion Diameter:

1.625"

Pinion Spline:

30 spline

U Joints:

1310 series

Ratios:

2.50 - 4.56 : 1

Carrier Break:

2.50 - 2.76 | 3.42 -4.56

Identification:

12 bolt rear cover, passenger car version has a different cover and is easily distinguishable

GM 12 Bolt axle identification