What are the axles on a 1988 f250 4X4?

A 1988 Ford F-250 4x4 typically uses a Dana 50 front axle and a Dana 60 rear axle. However, there's a *small* chance of variations depending on options selected when the truck was new (like payload capacity). To be absolutely certain, you'd need to check the axle tags themselves, usually found on the differential housing.