What is "h-drive"

The centre spare wheels are unpowered, but can roll freely.]] An H-drive drivetrain is a system used for heavy off-road vehicles with 6×6 or 8×8 drive to supply power to each wheel station.

H-drives do not use axles but rather individual wheel stations, usually carried on a punt chassis. A single differential splits the drive into separate left and right drive shafts, which each run fore and aft inside the bottom corners of the chassis. At each wheel station a bevel box drives the half shaft out to the wheel.