Dear Doctor: My 2002 Chevy Avalanche has 107,000 miles on it.

When driving at highway speeds or over rough roads there is a severe vibration in the front end. The vibration lasts a few seconds and can be felt in the floorboards. Passengers also feel the vibration. I took the truck to the dealer and they suggested a wheel alignment. Now the problem is worse. The steering feels looser than before the unnecessary alignment. Could the problem be a shock or ball joint? -- Jason

Dear Jason: The complaint you mention is from a worn front-end component, not a bad alignment. You need to have the front end checked by a qualified technician. If your steering system has a steering shock stabilizer, then it may also be worn. A common complaint in GM vehicles is "play" in the lower steering shaft knuckle. This will cause a rattle and looseness in the steering wheel.

Dear Doctor: I recently purchased a 2002 Dodge Dakota V-8 4x4 with 45,000 miles. I know that Dodge had problems with the front suspension. Is there anything I have to look out for? -- Richard

Dear Richard: The front-end parts have been known to wear prematurely. Chrysler had some recalls on certain trucks' ball joints. Check with the dealer for any recalls on your truck. If ball joints are needed, try to buy ball joints with grease fittings.

Dear Doctor: I own a 2000 Lexus RX 300 that has been a great sport utility vehicle. About three years ago a clicking or snapping type noise started coming from the cargo area. Every time I take it the shop the noise does not occur, but the noise is driving me crazy. Have you every heard of this problem? What is the best way to have the noise located? -- Donna

Dear Donna: When we have vehicles like yours it often takes one drive and one technician to ride in the vehicle to locate the source of the noise. Suspension noises, such as sway bar links and bushings, are very common failure items in Toyota and Lexus vehicles.

Dear Doctor: I own a 1994 Acura Legend with 113,000 miles. There is a small leak in the rear main engine seal. Is there any chemical that will stop the leak? Al

Dear Al: If the leak is from the rear engine crankshaft seal, then there is no additive that will fix a rear main oil seal leak. I suggest switching over to high mileage engine oil.

Dear Doctor: I own a 1992 Acura Vigor that has an ongoing heater blower problem. Recently, I took the car in for service and they replaced the blower motor but the problem still exists. I returned to the shop and they said there is most likely an electrical short and it will be expensive to repair. Arlene

Dear Arlene: It sounds like there is a break in the current from the heater blower switch to the heater motor. In between the heater blower and switch is a blower resistor that has been a problem in many vehicles. In some rare cases a poor connection at the fuse or ground can also cause the problem. A few simple tests will be needed to find the problem.

Dear Doctor: I own a 1997 Ford Taurus with 78,000 miles. The ABS light will come on when driving between 60-70 mph and stay on until I shut the car off and restart it. I took the car to the shop and they said the cost of repair would be around $1,000. They also said just to drive the car as it is without the anti-lock brake feature. What do you suggest? Scott

Dear Scott: Did the technician actually check the computer for trouble codes? It sounds like there could be a simple ABS tone ring located on the axle or a speed sensor. If the problem were either one, the cost would be in the area of $350, not $1,000. If you choose not to make any repair, then the brake system would work as it would without ABS.

Dear Doctor: I own a 1996 Ford Ranger pickup with 125,000 miles. I've been told by several Ford technicians not to worry about the timing belt or timing chain. What do you advise? Wally

Dear Wally: If the engine is a four-cylinder and has a timing belt, by all means replace it. If the engine is a V-6 with a timing chain, then there is no interval replacement.

Dear Doctor: I own a 2005 Toyota Avalon. Since new, there has been a brake groan and squeak noise when I release the brake from a stop. I have been back to the dealer three times with no satisfaction. They say there is nothing wrong and that this noise is normal. What are your thoughts? Harry

Dear Harry: The noise you are hearing is from the brake pad lifting off the brake rotor. Different brake pads may help to eliminate the groan or squeak the Toyota brake pads cause. The new pads must fit securely into the brake anchors and all brake pad hardware must be in good condition. There is no safety factor relating to the brake noise as long as the brake pads are not worn out. Make sure the shop uses a good quality brake pad such as Bendy or Raybestose.

Send questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347