when should you put a car in h4

H4 (4-High) is for when the surface turns slippery or loose—think gravel, wet clay, snow, beach sand, or corrugations—at normal road speeds.

On part-time 4WDs without a centre differential, use H4 only off-road or on low-traction surfaces; using it on dry sealed bitumen can wind the drivetrain tighter than your jeans after Christmas.

Drop back to 2H when traction returns, and save L4 (4-Low) for steep climbs/descents, ruts, or crawling with heavy loads.

Some full-time/AWD setups allow H4 with an open centre diff on-road, but locking diffs on high-grip surfaces is still a no-no—always follow the owner’s manual for shift speeds and specifics.