Our donor Chevy Silverado was built in 1989, wore the 2500 badging, and featured six-lug w
The GM Corporate 14-bolt axle is one of the most favored rear-ends you can find used for under $500. Most wrecking yards have a pile of them in stock, and due to a substantial production run across all variations of HD pickup trucks and SUVs, chances are you can find the specific type you need with minimum effort. Enthusiasts love the full-floating eight-lug 14-bolt because it features a massive 10.5-inch ring gear, and a very strong pinion design that incorporates support bearings on each side of the pinion's teeth-awesome for minimizing pinion deflection under high torque applications.
However, most people are not aware of the less common six-lug, semi-floating version of the 14-bolt axle. GM called it the "9.5" 14-bolt (after its ring-gear diameter) and offered it exclusively in light-duty 3/4-ton pickups built between 1986 and '93. While not as strong as its eight-lug cousin, the semi-floating 14-bolt rearend does sport some noteworthy attributes. For instance, the all-important width measurement from wheel mounting surface to wheel mounting surface is 67 inches-perfect for most 1/2-ton pickups. Generally, you wouldn't even need to change mounting brackets to bolt this housing right into the rear of a 1/2-ton GM pickup because the leaf spring architecture is identical. We like the fact that the ring gear measures out at a healthy 9 1/2-inch diameter, and the 33-spline axleshafts have a 1.370-inch diameter-a sure improvement in strength over the typical 1/2-ton shafts. This less grown-up version of the 14-bolt may not have the extra pinion support bearing of its eight-lug cousin, but it's rated to handle 5,000 lb-ft of torque, so it's no lightweight either. Moreover, aftermarket suppliers such as Randy's Ring and Pinion offer all the upgrade goodies you need to make this rear end survive with up to 37-inch-tall rubber. As a result, owners of virtually any GM 1/2-ton pickup offered with six-lug wheels can benefit greatly from a semi-float 14-bolt axle upgrade.
Here is the kicker: Thanks to the semi-floating design, a factory-style wheel will bolt right up. This means you do not have to spend your hard-earned cash on eight-lug wheels to get vast improvements in overall axle strength. We think these axles are the cat's meow for trucks equipped from the factory with 10- or 12-bolt rear axles. Yes, you'll need to ensure proper gearing for your truck, but know that most semi-floating 14-bolt axles have the common 1/2-ton 3.73:1 gear ratio already installed, rather than the popular 4.10:1 ratio found in the full-floating version-so if you already have 3.73:1 gearing, you may save additional money. Otherwise, depending on U-bolt length and pinion yoke type, the job is a no-brainer.
For this story, we borrowed a friend's '89 Chevy Silverado 3/4-ton with the less-common semi-floating axle installed from the factory (this is the donor truck you would want to find at a wrecking yard). Follow along now as our friends from Right Gear and Axle of Salinas, California, help us fortify a semi-floater for 35s, light towing and occasional trail work.
With the vehicle secured properly on a lift, Right Gear's technician started the teardown
Randy's Ring and Pinion also supplied us with a pair of their 1541H alloy axleshafts for t
Once the pumpkin was drained, we noticed a large amount of metal debris attached to the ma
With both axleshafts and the factory open differential removed from the housing, the techn
Next, the technician turned his attention to readying the differential for new parts. Here
As the axle was being prepped for the new parts, another technician installed the new ring
With the locker in place in the differential housing, the technician figured out exactly w
Setting up a good wear pattern is critical for trouble-free axle operation. As you can see
This photo shows how the ELocker wiring arrangement looked after the grommet was installed
Once the new differential locker was installed, the technician installed the new axleshaft
With the axle completely buttoned up, we added two quarts of Max-Gear synthetic gear oil b
One Royal Purple Lane
Randy's Ring & Pinion (Yukon Gear)
10411 Airport Road SE
1111 Superior Avenue
Right Gear And Axle
491 El Camino Real South