* Let's hope he meant hydraulic fluid to the hydraulic fluid resservoir! How much hydraulic fluid did you have to add? Over half a liter? Can you see any signs of hydraulic fluid leakage under the hood or under the car? Check hose from reservoir to pump, body of pump itself, and under the car from the transfer case back.
* If the hydraulic system is taking more fluid but it's not leaking out anywhere, it's storing it somewhere. The most likely place is inside the transfer case, where some older-design cases leak internally. Read through another current thread on "4matic".

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Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536