Dealer took reader for unnecessary service

Dear Tom and Ray: We purchased a new 2005 Jeep Liberty for our daughter last year and have faithfully taken it in to the dealership where we bought it for routine maintenance. At the time of the last maintenance checkup (11,784 miles), the repair shop performed rear and front differential service, at a cost of $240. They said it should be performed every 12,000 miles. I've never had routine differential service performed on any car I've ever owned. Is this legitimate?

Federico

Tom: Hmm. How to put this gently, Federico? Did the service manager have binoculars hanging around his neck? Because he definitely saw you coming.

Ray: Most cars never need differential service. That's a component that, under normal driving conditions, should last for the life of the car without needing any attention.

Tom: If you do what manufacturers call "severe duty driving," then Jeep does recommend changing the fluid in both differentials every 12,000 miles. But severe duty means you're doing things like extensive off-road driving, using the vehicle as a taxi, driving mostly in extreme hot or cold temperatures, or regularly towing around a couple of Angus bulls.

Ray: If that describes your daughter's driving, then the dealer is doing the service that Jeep recommends. But if your daughter is like 99 percent of America's drivers and uses the Liberty to go to school or work, or take road trips with her friends, then the dealer took you for a ride. And you should go back and ask for some money back.

Tom: For future reference, if you look in the back of your owner's manual, the recommended services for each mileage interval are listed there. So you can see for yourself what the manufacturer actually recommends at 12,000 miles. Look under Schedule A, which for Jeep is normal use.

Ray: If your daughter's Liberty doesn't do severe duty, and you don't get satisfaction from this dealer, remember that you can take the car to any mechanic you like for its regular service. It does not have to be done at a dealership. Simply hand them the owner's manual, point to your mileage interval and say, "These are the services I'd like you to perform." Keep the receipts, and it will have absolutely no effect on any free warranty work you need to have done by the dealer.

Listen to "Car Talk" at 9 a.m. Saturdays and 5 p.m. Sundays on KRCU 90.9 FM -- Southeast Public Radio. Write to Tom and Ray at Car Talk Plaza, Box 3500 Harvard Square, Cambridge, Mass., 02238. Or e-mail them at the Car Talk section of cars.com.