Pulls the side carrier bearings off a differential case so you can swap gears or reset shims; fits GM 8.2/8.5/12-bolt, Ford 8.8, 9-inch, and Dana axles.
Anyone who has tried to pull the side bearings off a Ford 8.8 or GM 10-bolt carrier with a three-jaw gear puller knows how it ends: the jaws slip off the narrow lip, the cage gets crushed, and the case gets gouged. The OTC 4520 is a dedicated differential side bearing puller set made for exactly that pocket. If you are regearing, installing a locker or posi, replacing noisy carrier bearings, or moving bearings to a new case, this is the tool that gets them off straight.
In a Ford 8.8 the differential case rides on two tapered roller bearings pressed onto its journals. When you swap to a locker or a new carrier, those bearings either have to move to the new case or be replaced, and when they are worn they are the source of the growl that changes with road speed. The 4520 uses two forged jaws that hook behind the bearing cone, a retaining yoke that holds the jaws square so they cannot spread, and a forcing screw that pushes against a step plate centered on the end of the case. The load goes into the inner race, not the rollers, so a good bearing can come off reusable. The same tool works on GM 8.2, 8.5, 10-bolt and 12-bolt cases, Ford 9-inch, and many Dana carriers, where shims sit between the bearing cone and the case and every reshim means pulling bearings.
Before you tear down, check backlash with a dial indicator and rock the carrier with a pry bar. Side-to-side play in the case or backlash that changes as you rotate the ring gear points to carrier bearings. Pitting or flaking on the cones once the caps are off confirms it. If the noise changes between throttle and coast instead, look at pinion bearings and gear contact first.
The 4520 is listed for GM 8.2, 8.5, 10-bolt and 12-bolt, Ford 8.8 and 9-inch, and many Dana carriers. On some tight Dana and Spicer cases the bearing sits in a shallow groove; there, thin the jaw tips slightly or clamp the jaws close to the base so they stay under the cone, then run the screw with an impact. Check that your bearing cone has a lip the jaws can reach within the 1-5/8 in reach. For carriers where the jaws cannot get behind the cone at all, a clamshell carrier bearing puller is the alternative. See all of our differential and transmission tools.
| Brand | OTC (Owatonna Tool Company) |
| Part number | 4520 |
| Type | Differential side carrier bearing puller, 2-jaw |
| Includes | 4520-1 forcing screw/cross block, two 4520-2 jaws/pins, 4520-3 retaining yoke, 4520-4 four step plate adapters, storage case |
| Crossbar spread | 2-5/8 in inner holes, 3-3/8 in outer holes |
| Reach | 1-5/8 in |
| Forcing screw | 3/4-16 thread, 6-11/16 in long |
| Step plate sizes | 15/16-1-11/32, 1-1/8-1-1/2, 1-1/4-1-5/8, 1-1/8-1-3/4 in dia |
| Fitment | GM 8.2/8.5/10-bolt/12-bolt, Ford 8.8 and 9-inch, many Dana carriers |
| Weight | 4.9 lb |
Yes. Ford 8.8 and 9-inch are on its listed fitment, along with GM 8.2, 8.5, 10-bolt and 12-bolt and many Dana carriers.
Often yes, because the jaws load the inner race rather than the roller cage. Inspect the rollers and cone for pitting before reusing, and replace cones and cups as matched pairs.
Some Dana and Spicer cases have a shallow groove behind the bearing. Grinding the jaw tips thinner or clamping the jaws close to the base helps them stay under the cone. Otherwise use a clamshell style puller.
Yes. The screw is a 3/4-16 thread, 6-11/16 inches long, and can be driven with a breaker bar or an impact wrench. Keep the retaining yoke snug so the jaws stay square.
No. It is a puller only. Press new carrier bearings on with a bearing driver or press that loads the inner race.
