Q. My 1994 Ford Ranger “Splash” which I bought new, just recently went through the state inspection program. My truck passed with flying colors. The truck has 85,000 miles and in fact it still has the original tires, brakes and shocks. When should I change the transmission fluid? The owner’s manual doesn’t have a recommendation.

A. There are two schools of thought on when to change transmission fluid. One is to change it every 30,000 miles. The second is that if the fluid has never been changed, leave it alone. The theory is that since transmission fluid is a cleaner, it may wash out some of the varnish that is holding the transmission together. My recommendation is a combination of both. If the fluid is clean, leave it alone (there is no specific recommendation from Ford). If the fluid has started to become discolored and “burn,” change it. Since your truck is 15 years old I would also consider replacing the tires, since they tend to dry-rot and crack. I would also give the brakes and shocks a very careful look. Shocks and brake responsiveness tend to change gradually and most drivers don’t notice as the ride and handling start to degrade.

Tie rod rip-off?

Q. I have a 1984 Ford Escort that I have owned since new. At 120,000 miles I replaced the ball joints and tie rod ends. At a recent state inspection (136,000 miles) I was told the tie rods and ball joints would need to be replaced. I have the car serviced every 3,000 miles; shouldn’t the new parts last longer than 16,000 miles?

A. The replacement parts should certainly last longer than 16,000 miles. Incorrect installation, dirt and moisture are some of the factors that can cause rapid component wear. Although I hate to think this happens, it could be that the inspector was “overly critical.”

PT shaker

Q. I have a 2006 PT Cruiser convertible. I have owned it since new and recently replaced the tires. After having the tires rotated about six months ago, the car started to shake at 55-60 miles per hour. I have had several people look at the car, had the tires replaced and the wheels aligned and the car still shakes. I have spent over $1,000and the car is driving me nuts. At this point I feel this will be my last Chrysler!

A. Common sense says that the vibration is most likely related to the tires, since it wasn’t there before the tires were rotated. I would start with rebalancing the tires with a high quality wheel balancer such as the Hunter Road-Force. This balancer puts the tires under stress as they are being balanced. A good tire technician will also match wheels and tires to minimize high spots as well as measuring wheel run-out when the tires are mounted on the vehicle. The Chrysler dealer should also have a vibration meter. The meter reading should help the technician determine if the vibration is tire related or may in fact be something else such as an axle shaft.

Test the ABS sensors

Q. My question concerns my ABS brakes. After having my tires rotated last year, I started to experience my brakes acting up at various times (sometimes weeks between). The road can be wet, dry, bumpy, smooth, downhill, straight, railroad tracks, manhole cover, etc. When I step on the brakes they shudder and I have to press as hard as I can to stop. I have had my car checked out by my dealer and the brakes have not responded badly during their road test. No diagnostic code comes up on the dash so they are at a loss to advise or fix the problem. The dealer says “don’t worry, it will stop.” I spoke to a few relatives who are mechanics and they say it’s the ABS, but they don’t know how to adjust it. I would truly appreciate any answer or suggestions.

A. The most common problem is that one of the ABS wheel sensors may be slightly out of the specification. The challenge is that until the ABS system sets a code, a technician will need to test all the sensors individually, which can be expensive and time consuming. These sensors can become contaminated by rust and could have even been damaged when the tires were rotated.

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