10.5" Corporate 14 Bolt Differential

10.5” Corporate 14 Bolt Differential is a heavy duty differential that is used by Chevrolet and GMC. This differential is of the full floating design and has a ring gear with a diameter of 10.5 inches. As the name implies, this differential has 14 bolts holding on the differential cover. The ring gear is not held on with 14 bolts, but rather 12. This is a very heavy differential that weights in at around 550 lb depending on the brake options and axle width.

Applications

The 10.5” Corporate 14 bolt differential has been used in Chevrolet and GMC trucks and vans since 1973.

10.5” Corporate 14 bolt compared to other GM truck differentials

* 8.5” 10 bolt semi floating rear differential has a torque rating around 3,800 ft·lbf
* 9.5” 14 bolt semi floating rear differential has a torque rating of just less than 5,000 ft·lbf
* 10.5” Corporate 14 bolt full floating rear differential has a torque rating 6,242 ft·lbf
* 11.5” 14 bolt full floating rear differential has a torque rating 8,321 ft·lbf

Full-floating vs. semi-floating

The 10.5” Corporate 14 bolt differential is of the full-floating design. The full-floating design is used in heavy duty applications as opposed to many of the lighter-duty differentials that are semi-floating. A full-floating differential can be identified by the large hubs that stick out the end of the axle and have the axle shafts bolted to them. These axles are able to carry more weight then a comparable semi-floating differential due to the fact that the hubs on the ends of the axle have their own bearings that carries the load of the vehicle. The semi-floating design carries the weight of the vehicle on the axle shaft, there is simply one bearing on the end of the axle tube that carries the load from the axle and that the axle rotates through. In the full-floating design the hubs carry the weight of the vehicle while the axles are only used to transmit torque and rotation from the carrier in the differential to the hubs on the ends of the axle. Full-floating axles are held in place by bolting a flange on the end of the axle to the hub. With a semi-floating axle, the axles are held in place by c-clips that are in the differential carrier. If an axle or c-clip ever breaks it is possible that the wheel of the vehicle could leave the vehicle. The full-floating designs, however, do not have c-clips, but can still break axles. If the axle shaft breaks, the wheel will not go anywhere since it is still bolted to the hub.

First design/second design

The first design was produce from 1973 to 1985. The first design remained unchanged until 1986. This design had drums that were held on by the wheel studs and had a smaller diameter pinion bearing than the second design. The second design was produced from 1986 to present. One change that occurred in the second design was that on some models the brake drum could be removed without having to remove the hub and axle shaft. Additionally, the pinion received a larger diameter bearing while the pinion stayed the same diameter, which increased the durability of the pinion.

Brakes

All of the 14 bolt differentials typically have drum brakes except for the newest models which have disc brakes. The first design of this differential had three different diameter brake drums. At first the differential was released with drums small enough to fit 15” wheels. Then after a few years a larger drum was standard on the ¾ ton along with the even larger drum on the 1 ton. This is an area of the axle assembly that is commonly converted by the enthusiast to disc brakes.

General specifications

* 1.5” diameter axles
* Axles are 30 spline axles
* Axles are different lengths from side to side
* 10.5” diameter ring gear
* 1.590” diameter shank on the pinion
* Pinion supported with bearings on both sides of the teeth which minimizes pinion deflection
* Removable pinion support

Ratios

The ratios that are available for this differential include: 3.42, 3.73, 4.10, 4.56, 4.88, 5.13, and 5.38. There are two different cases for this differential depending on the gear ratio of the differential. For gear ratios of 4.10 and lower case number 6258336 is used, while for 4.56 gears and higher case number 6258340 is used.

Advantages

*Strong 10.5" ring gear and pinion
*Strong Axles - 1.5" diameter, 30-spline
*Stout Housing - large 3.25" x 0.5" tubes
*Additional bearing on end of pinion for support
*Removable Pinion
*Easily converted to disc brakes
*Common to find with 4.10 and 4.56 ratio
*Easy to changes gears
*Built in carrier preload adjusters
*Cheap and Plentiful
*Can be shaved to increase ground clearance by about 2"

Disadvantages

*Heavy - around 550lbs.
*Low ground clearance
*Lack of aftermarket parts that are available to other differentials
*Large, heavy brake drums
*Gearing only available down to 5.38

ee also

* Powertrain
* Gear train

External links

* http://www.4wheeloffroad.com/techarticles/drivetrain/131_0605_gm_14_bolt_axle_rebuild_parts/index.html
* http://www.chuckschevytruckpages.com/14bolt.html
* http://www.thedieselpage.com/reviews/randys.htm
* http://www.akfabshop.com/alaskaoffroad/axle_tech.htm
* http://www.4wheelnoffroad.com/axle.html#GM
* http://www.pirate4x4.com/tech/billavista/14b_bible/index.html