what is a reasonable cost for a valve cover gasket repair? on 2004 BMW X3

The dealer also stated that transfercase is leaking. They need to determine where it is leaking? I understand that replacing the entire transfercase is 2-3 thousand. I feel that I am at the mercy of the dealership and I don't know what to do. How do I know if they are telling the truth?

Asked by for the 2004 BMW X3
The valve cover gaskets for either the 2.5l or 3.0l engines are 2.1 hrs labor. The gasket should be around $40-50. It is highly recommended that an oil change be performed at the same time. You may also consider performing a tune-up at the same time. The plugs need to come out anyway. There are also incidental o-rings that should be changed also. Total price @ $95 hr should be less than $400 (incl plugs & BMW Synthetic Oil). Leaking transfer case could range from something as simple as axle seals or gaskets to actuator motor housing. Defective TC's are fairly common with this model. Sorry, probably not what you wanted to hear. There are many European Specialists. Check your area for independents that specialize in European.