The speed difference between H4, L4 and crawl mode in the Arctic Trucks Land Cruiser 300 AT35! H4 (High-speed 4WD) is designed for driving on slippery, unpaved roads (snow, sand, light mud) at normal to high speeds, engaging all wheels without significant power reduction. L4 (Low-speed 4WD) is for extreme off-roading (deep mud, steep, rocky inclines) requiring maximum torque at very low speeds, and usually requires a complete stop and neutral gear to engage. Crawl Control is an automatic, electr