Rear and Front differentials Fluids and Transfer Case Fluids should be changed every 30,000 miles. If you use your vehicle in areas where water could enter into the fluids it is strongly recommended to change the fluid when there is this possibility. Repairs on these items are almost always very expensive and can be avoided by changing your fluid regularly. When servicing your vehicle you should have them check the fluid levels and possible signs of water in the fluids. Commercial vehicle should always service these fluids if hauling or towing. Some Commercial vehicles are used in construction areas that put have large puddles of water that can get into your fluids and if not changed it will cause damage.
