Rear Crush Sleeve (YSPCS-045) by Yukon Gear and Axle. Size: 0.625in. Yukon shim kits are precision machined and tailored for each individual application to ensure you have the right shims for every set up. Yukon Gear and Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.