Rebuilding Factory Axles on an M1028 Military TruckPosted in How To: Transmission Drivetrain on March 20, 2019
The hunt for the toughest rig possible begins from the ground up. Rugged off-road tires replace tear-happy street rubber, and before long, escalating antics yield a broken axleshaft, hub, ring gear¬, or worse. The upgrade buzzer rings. Catalogs pages ripe with beefed-up parts are torn from their bindings.
Off-roading abuse inevitably takes its toll. However, starting with a rig built tougher from the factory can often cut down on upgrade costs as well as provide a much better platform to begin a build. In our case, the perfect canvas was an M1028 CUCV. A square-body Silverado by any other name, the CUCV was Chevy’s military ride and served honorably in the armed forces for years. Near as we can tell, our unit delivered well over 400,000 miles of hard work before being retired from duty. While in need of a full rebuild to just about every major system (what 400,000-mile truck wouldn’t be?), the truck was the desirable M1028 model. It had all the right hardware boxes checked, including a Dana 60 front axle (ours actually had a limited slip in it, although the clutches were fried), a 14-bolt rear axle with a Detroit Locker, a TH400 transmission, and a 6.2L diesel engine (although that’s only a plus if 165 hp gets your blood pumping).
The truck needed a lot of work because you can’t build a house on sand. The axles were deemed the most reasonable place to start. We pulled them out and stripped them down. With the help of some G2 Axle & Gear 5.38 gears, an Eaton Detroit Locker for the front, and some friends with better tools than we own, we began piecing the axles back together.
To begin the rebuild, friend and head mechanic Agapito Arteaga removed the axleshafts and carrier and blasted the axle with a pressure washer.
GM’s 14-bolt axles employ a drop-out pinion assembly. This was detached from the housing, then the yoke was removed and the pinion pressed out.
Our new 14-bolt pinion assembly was mated together with a hydraulic press and reinstalled in the 14-bolt housing.
With our 14-bolt rear axle set up, it was time to move on to the Dana 60 front axle. It was treated to the same disassembly and cleaning as the front.
Setting backlash on a Dana 60 axle is a little more difficult than the 14-bolt. Shims are installed behind the carrier bearings that locate it laterally in the housing. Since the bearings are pressed on, that means changing the shims would require pressing the bearings on and off. One way to cheat this is to take your old carrier bearings and grind them just large enough so that they slide onto the carrier. Use these mockup bearings to find the necessary shims required.