2006 GMC Envoy Fluid Requirementsby John Walker
Fluid and fluid level recommendations vary by vehicle and engine size. The 2006 GMC Envoy uses a 4.2 L, six-cylinder engine or 5.3 L, eight-cylinder engine. Identify the engine by the sticker under the hood or by counting the number of spark plug wires (six-cylinders have six; eight-cylinders have eight). The manufacturer recommendations for fluids include engine oil, transmission, transfer case, differentials and the hydraulic systems.
Oil and Transmission
The 4.2 L engine uses 7 qts. of SAE 5w30, and the 5.3 L uses 6.1 qts. of the same oil. The levels include a filter change. Higher mileage engines should use an oil additive to recondition the seals inside your engine. Subtract the size of the additive from the recommended amounts of oil. The transmissions of both vehicles call for a low-viscosity automatic transmission fluid. Fill amounts for a total fill is 11.3 qts. of low-viscosity ATF.
Transfer Case and Differential
The transfer case uses the same oil as the transmission. The differentials use SAE 75w90 synthetic gear oil. The transfer case and differentials have fill plugs located toward the top-quarter of the case. Fill the case until the level of fluid is flush with the bottom of the plug hole. Use an L-shaped Allen wrench to measure the level when filling by sticking the short end of the Allen wrench into the hole. A little fluid should be present on the tip of the Allen wrench when the case is full.
The hydraulic systems include the power steering, brake and clutch. Both brake and clutch systems use DOT-3 brake fluid. Standard power steering fluid is use for the power steering reservoir. Fill to the full-line when adding fluids. The systems require bleeding if you change out any parts. Monitor the reservoir closely when bleeding the systems. Do not allow them to drop beneath half-full.