Does downshifting do damage?
Dear Motormouth: Iowna car with an 8-speed automatic transmission and manual shifters. If I am approaching a red light 50 to 100 yards away, am I better off downshifting or gently applying the brakes? Does repeated downshifting do long-term damage to the transmission?
— P.J., South Windsor, Connecticut
Dear P.J.: Many transmissions remain in the drive mode or can be switched to manual setting, allowing you to select your own shift points. The technology is an outgrowth of Formula 1 racing. You may leave the gear selector in drive and still operate the manual shifters. The transmission will revert to drive without harm. When the cruise control is set, the car may downshift on its own to take advantage of engine braking when descending a hill. The short answer is yes, you may downshift approaching a red light. I put my transmission in manual mode and use the paddles exclusively on twisty country two-lanes.
Dear Motormouth: I own an Audi Quattro and a Toyota SUV with all-wheel drive. Both vehicle manuals state to rotate the tires front to back and vice versa. I buy my replacement tires at Costco and they insist that AWD vehicles have the tires crisscrossed when rotating. Which method is correct for these types of vehicles?
— T.F., Virginia Beach, Virginia
Dear T.F.: Rotating your tires ensures that they wear evenly at the same rate. That’s important on all-wheel-drive vehicles since replacing only one
or two tires is prohibited. Audi’s front-to-rear and rear-to-front meet these needs. But Bridgestone, the brand that Costco sells, says: “Recommended for 4-wheel and all-wheeldrive vehicles … all tires are moved diagonally.” Both techniques are acceptable.
Dear Motormouth:
Regarding the query from a reader about why people leave 20 feet of distance between cars at a stoplight: One reason may be that, with the increase in carjackings in many cities, police advise leaving room to maneuver in case someone tries to hem them in.
— V.P., Chicago
Dear V.P.: Many readers mentioned this. But I wonder how useful it is to evade a carjacker. It’s not easy to outrun a gun.
Dear Motormouth: I always use Top Tier gas from the same brand in my vehicles. But I was wondering, does it make sense to vary the brands to get a variety of additives/ detergents or does it not make a difference?
— M.U., Chicago
Dear M.U.: Gasoline is a commodity. All gasolines are the same until the additives are blended in. So all Top Tier gasolines have additives that meet those criteria. Short answer: Switching brands
is perfectly fine.
My state is increasing the amount of ethanol in our gasoline. I own a 2005 Subaru Forester and my parents have a 1995 Lincoln Town Car. Is this increase in ethanol going to have a negative impact on the engines?
— N.G., Westchester, Illinois
Dear Motormouth:
Dear N.G.: Check your owner’s manual for what the carmaker recommends. If your car is 2001 or older, do not use more than 10% ethanol — E10. That’s the most common blend of regular gas. In a pinch, one tank of E15 won’t hurt anything, but regular use could cause assorted damage in that 1995 Town Car. One more thing: The more alcohol in the gas, the lower the fuel economy. If you want to search for gas stations that don’t sell E15, try the Gasbuddy app.
Bob Weber is a writer and mechanic who became an Ase-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weber’s work appears in professional trade magazines and other consumer publications. Send questions along with name and town to motormouth. tribune@gmail.com.