GM 14 Bolt Axle

GM 14 Bolt Axle, Differential Specs

The GM Corporate 14 bolt is a heavy truck axle designed, developed, and produced by General Motors. It is particularly attractive in off-road applications as a result of its full floating axles and brute strength, despite tipping the scales at a hefty 550 lbs. It can support large tires, is suitable in high torque applications, and decades of production has made it readily available.

The General Motors Corporate 14 bolt is a heavy duty, full floating rear axle used in 1973 to 2001 Chevrolet and GMC pickups. It is not to be confused with the smaller, semi floating 14 bolt axle, which uses a 9.5" ring gear and is built for 3/4 ton applications. The Corporate 14 bolt uses a 10.25" ring gear and unique pinion bearing design such that the pinion shaft is supported from the front and rear. It is GM's 1 ton axle and carries a GAWR up to 8,600 lbs. There are not a lot of variations of this axle, which makes it simple to source and build a 14 bolt rear end. The 1973 to 1985 14 bolt design remained relatively unchanged, while the 1986 and newer model received larger pinion bearing design. At around 550 lbs, the axle is heavy - but its strength allows it to turn 44 inch tall tires on the highway with ease in stock trim.

GM 14 Bolt Specs


1973 - present GMC & Chevrolet trucks (AAM axles replaced the 14 bolt in most applications for 2001+ model years)

Full/Semi Float:

Full floating rear axle


up to 8,600 lbs

Ring Gear:


Axle Spline Count:

30 spline

Axle Shaft Diameter:

1.50" or 1.34"

Axle Tube Diameter:

3.25" diameter, 0.50" wall thickness tubes

Pinion Diameter:

1.750" pinion

Pinion Spline:

30 spline


3.21 - 5.38 : 1

Carrier Break:

3.21 - 4.11 | 4.56 - 5.38

Max Torque Capacity:

6,242 lb-ft


~ 550 lbs


14 bolts hold differential cover, housing has a unique octagonal shape.

14 bolt axle diff pan bolt pattern