We chose a Dana 50 front differential...
We chose a Dana 50 front differential from an '80 to '96 Ford F-250 for our differential rebuild.
Every diesel truck on the road today has a differential and ring and pinion gear set in the rear axle. Four-wheel-drive trucks add a second set of gears and another differential to the front axle to transmit engine torque to all four wheels. Yet differential modification and repair is one of the most feared and least understood aspects of diesel trucks.
The truth is, setting up ring and pinion gears and installing traction-adding differentials isn't hard-but it is a pain and requires special tools that can mean a big investment of cash. To see how difficult installing new gears and a differential would be at home, we chose a Dana 50 front differential from a Ford F-250 to use as a guinea pig.
In order to do the job, we used the following tools and resources: Auburn Ected differential installation guide, vernier caliper, gear-marking compound, 3/8-inch-drive torque wrench (calibrated in inch-pounds), 1/2-inch-drive torque wrench (calibrated in foot-pounds), three-jaw puller, Dana 50 Spicer axle service manual, Differentials by Randy Lyman and Jim Allen, a piece of reduction exhaust tubing, a bearing and race driver, and a Starrett dial indicator.
We ordered a 4.88 Yukon ring and pinion gear set, a master install kit (bearings, seals, ring gear bolts, and shims), a new Spicer pinion yoke, and Timken setup bearings from Randy's Ring and Pinion. We also called Auburn Gear to order an Ected locking differential to install with our new gears and bearings. Then we set up a workspace on a small table in our kitchen and spent the weekend setting up our differential. Here's what we learned.
 Truck differentials are composed...  Truck differentials are composed of three parts: the ring and pinion gear set, the ring gear carrier, and the bearings that hold everything in relation to each other. In order to get the gears to mesh properly, the bearings in a Dana differential are held in position using selective thickness shims that go between the carrier bearings and the carrier. Setting up the ring and pinion gears typically requires you to fit various combinations of shims under the carrier bearings until the gears mesh properly. To make swapping the shims around easier, Randy's Ring and Pinion offers Timken setup bearings that have been modified to slide on and off the carrier by hand until the desired gear pattern is achieved. When setting up new gears, it's best to use the original shims as your baseline and adjust them as needed. |  We began our gear and locker...  We began our gear and locker assembly by installing the pinion gear in the Dana 50 centersection. John Hughbanks at One Ton Offroad helped us out by pressing the inner Timken bearing onto the Dana 50 pinion gear. Then we drove the two bearing races into the Dana 50 centersection and used these solid pinion-bearing shims between the inner and outer pinion bearings. |  With the pinion bearings,...  With the pinion bearings, races, and preload shims installed, we fitted a new Spicer 1310-series yoke from Randy's Ring and Pinion and torqued the pinion nut to 200 ft-lb using two bolts and a prybar to hold the yoke. |