S10 Truck Pinion Alignment Shims (for all S-10s including 4-cylinder, 6-cylinder, and V8) sold by the pair

Why You Might Need One. Axle alignment shims are required to adjust driveline angles on swaps. 

Advantages of improved driveline angles are:

1. Reduced driveline vibration
2. Less wear on driveline parts
3. Better power transfer to the rear wheels
4. Improved fuel mileage

Why JTR Stealth? Several companies make pinion alignment shims. Most are made of cast aluminum or zinc and are too narrow to cover the entire width of the 2-1/2" wide leaf spring used on the S-10.

When these 2" wide aluminum shims are installed on the cast or extruded lowering blocks, the shims (or the lowering blocks) will fail because only a small portion is supported by the hollow lowering blocks. See below.

When the shims (or lowering blocks) break, the U-bolts can appear to loosen.

Stealth Conversions alignment shims are 2-1/2" wide and made out of high-strength solid aluminum, which will not fail in service.

Why Stealth Conversions Lowering Blocks? Note that the center hole of shims must be drilled out to 9/16. Some available cast and extruded lowering blocks do not have a pin height tall enough to protrude through the pinion alignment shim. 

The Stealth Conversions lowering blocks are unique in that the top of the block is threaded. This allows the pinion alignment shim to attach to the lowering block while leaving the full height of the cap screw for the rear-axle locating hole. See below. Click to read more about our selection of lowering blocks and order them. 

Installation Tips. When installing the shim onto the leaf spring pack, hold the spring pack together with a pair of Vise Grips® or C-clamps before removing the original bolt. See below.

The original bolt may be too corroded to remove without breaking -- or a longer bolt may be necessary. Stealth Conversions pinion alignment shims should be installed directly to the leaf spring with a 2-1/4" socket head cap screw. See below.

If lowering blocks are used, the alignment shim should be installed on top of the lowering block. Stealth Conversions Lowering blocks are designed to allow bolting alignment shims directly to the lowering blocks.