The 1994 Chevy Silverado's axle oil weight depends on the axle type and the rear axle ratio. Chevrolet used several different axles in that year.
You MUST check your owner's manual or the sticker on the driver's side doorjamb for the correct specifications for your specific truck.
The manual will tell you the correct weight and type of gear oil (some may require limited-slip additive). Guessing could damage your axles.
