ARBs Air Locker Differential Spreader is a professional automotive tool that no differential installer should be without. Most common Salisbury style axle assemblies (e.g., Dana Spicer model 44) require the use of a differential spreader in order to achieve the required carrier bearing pre-load during set-up. Stretching the housing casting (or pumpkin) open by sufficient enough force as to allow extra shim to be added to create the pre-load is the method that the OEM manufactures endorse, and most manufacture's have included special spreader sockets in the housing for exactly this purpose. Insufficient pre-load can result in bearing failure, or ring and pinion failure on any differential, and possible oil/air leakage issues in an Air Locker Differential. As a part of ARBs Air Locker Tools range of differential service/installation equipment, this specialty tool offers an easy, quick and highly effective way of pre-loading these axles. ;