Motoring Q&A: Window wonders about maintenance

Q: In 2009, we purchased a new 2008 Ford Edge. My husband followed all required maintenance. He passed away last year, and last October, I took the car in for a complete check and oil change. The mileage was 37,244 at the time. I am 81 years old and generally only drive around our retirement area. The current mileage is just under 39,000, and I realize just short stop-and-go driving is not good for a vehicle and need advice as to how often I should do oil changes, tire rotation etc. The tread on the tires shows very little wear but they are the original tires and while the car is kept in the garage at all times, I was told that tires need to be replaced at 10 years regardless of tread amount. I would appreciate any and all advice you can offer.

A: I'm sorry for your loss. My recommendation is to have your vehicle serviced once a year including oil/filter change, tire inspection (rotate every two years) and follow time/mileage recommendations for inspection of coolant, brake fluid, transmission and differential fluids. Several of these fluids are virtually "life of the vehicle" and won't need changing.

This annual service will give technicians the opportunity to check your vehicle over completely to ensure your confidence in it and its continued reliability.

Q: I purchased a 2016 Chevy Sonic with a standard transmission. The owner's manual instructs you to put the transmission in neutral, turn the ignition switch to "Accessory" and take out the DLIS fuse for towing. I plan on towing it behind a motor home on all four wheels. Why would the switch have to be put on "Accessory" on a manual transmission? No one from the Chevrolet dealership I purchased the Sonic from could answer this question.

A: The ignition switch must be in that position to unlock the steering. Pulling the DLIS fuse will interrupt power to the BCM — body control module. Doing this prevents any lights, fans or other electrical components from operating, to prevent the battery from discharging while the vehicle is being towed. An online search turned up information on installing a simple fuse bypass switch to eliminate having to pull then reinstall the fuse every time you tow the vehicle.


Q: In your May 7 column, you stated that shifting into neutral at stoplights serves no useful purpose for a vehicle's automatic transmission. I normally do this and I note that the transmission seems to release some kind of pressure it has been holding while in gear and the motor runs "easier." Doesn't this mean that there is something "working" in the transmission while it is left in gear when stopped and by shifting into neutral this releases something that is working and takes pressure off this mechanism — thereby saving some "wear and tear" in the transmission over time?

A: No. Nothing in the automatic transmission is "working" when the engine is running and the vehicle is stationary. As I said in my previous column, the only "active" components are the torque converter (mounted on the back of the crankshaft/flexplate) that drives the transmission and the transmission oil pump.

What you are feeling is the hydraulic pressure developed in the torque converter as the impeller rotates at idle speed but the turbine isn't turning. This action at idle doesn't really generate any wear and tear on mechanical components.

But as I stated earlier, every time the transmission shifts gears — including shifting from park/neutral into drive or reverse, the hydraulically applied clutch packs or bands slip a bit to smoothly engage that gear. Thus my feeling is that leaving the transmission in gear while stopped momentarily reduces that total amount of slippage the transmission planetary gears experience. In addition, the car is set and ready to move if you need to accelerate quickly.

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