Maintenance tune up

Check your owner's manual an see what Buick recommend at that mileage Check here http://repairpal.com/automobile-owners-manuals-online or try this link you may be able to down load a free copy of the owner's manual for your vehicle http://www.autousermanual.com/ I would certainly change the engine oil and filter and transmission oil. It probably doesn't call for a spark plug change yet but I would change the plugs, air filter, cabin air filter, flush the brake fluid and antifreeze.