What kind of oil should be added to the transfer case?
3 Answers
The transfer case should be filled with ATF (Automatic Transmission Fluid). Below is relevant information about transfer cases: 1. Judging from the gear lever of the transfer case, it more closely resembles a traditional part-time four-wheel drive system. The difference is that it is equipped with a center differential. When 4H is engaged, it can not only drive at high speeds on gravel roads but also achieve the function of four-wheel drive on regular highways. The 4HLC and 4LLC options it provides are four-wheel drive modes with the center differential lock engaged. At this point, its functions are the same as the 4H and 4L of a part-time four-wheel drive system. 2. The transfer case is a device that distributes the engine's power, directing it to the rear axle or simultaneously to both the front and rear axles.
Adding oil to the transfer case requires careful attention. Having driven hardcore off-road vehicles for over a decade, I can tell you the transfer case is like the backbone of a vehicle – it must use dedicated gear oil. Common transfer case oils typically require GL-5 rated 75W-90 or 80W-90 specifications. For 4WD vehicles, you also need to distinguish between manual transmission transfer cases and electronic transfer cases with multi-plate clutches. Last year when I changed the oil, I specifically chose full synthetic oil – this stuff has significantly better high-temperature resistance than mineral oil, making it particularly suitable for long-distance off-road conditions. Don't neglect the oil change interval either – under normal use it should be replaced every 60,000 km, but if you frequently drive through sand or water, changing at 40,000 km is safer. Never try to save money by using transmission fluid as a substitute – incorrect viscosity will wear out the gears.
As a pickup truck owner who frequently works on construction sites, the transfer case is my lifeline. When it comes to refilling the transfer case, it's essential to choose gear oil with moderate viscosity. I prefer using 75W-90 full synthetic oil. Remember these three key points: First, check the certification standard—it must have the GL-5 label. Second, look for anti-wear additives—they must contain sulfur-phosphorus components. Third, consider temperature adaptability—75W-grade oil offers better low-temperature fluidity in northern winters. Last week, I changed the oil myself—just unscrew the filler plug to pour it in. Note that there are two drain holes, one at the front and one at the back of the transfer case, and you must completely drain the old oil. Fill until oil spills out of the overflow hole—too little leads to insufficient lubrication, while too much can cause overheating. The mechanic said if the oil turns soy-sauce colored, it's time for a replacement.
