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Should I Change the Automatic Transmission Fluid?

By Junior Damato, September 29th, 2018

strong>Dear Doctor: The transmission fluid has never been changed on my 2006 Honda Odyssey with 145,000 mile. There are no problems with the transmission. Should I change the transmission fluid? Or, do a transmission flush? Bob

Manufacturer photo: 2006 Honda Odyssey
Manufacturer photo: 2006 Honda Odyssey

strong>Dear Bob: I suggest you drain the fluid (about 3 to 4 quarts will drain out, not the entire 12 to 13 quarts). The new fluid you add will mix in with the older fluid, verses a flush that changes 99 percent of the fluid. Doing a drain-and-fill will not shock the transmission. You can perform a drain-and-fill over the next three oil changes. Use only the Honda-factory fluid.

strong>Dear Doctor: I purchased a used 2005 Chevy Colorado pickup truck with the 2.8-liter four-cylinder and automatic transmission with 77,400 miles. Not knowing its history I changed the basics -- engine air filter; engine oil (5w30 synthetic Castrol Edge High Mileage); synthetic transmission fluid; rear-axle grease, spark plugs, and gas cap. When the "check engine" light came on, I replaced the downstream O2 sensor, and the upstream manifold O2 sensor. I was expecting city gas mileage to be around 17-18 mpg, but instead I'm only getting 12-13 mpg. I use 93 octane gasoline and Seafoam engine and injector cleaner regularly. The higher octane has no effect on the mileage. There are no fuel leaks and the transmission does not slip. Can you tell me why a four-cylinder engine only gets 12-13 mpg? Tom

strong>Dear Tom: Unfortunately, gas mileage on older Chevy Colorado trucks has been low driving around town, especially if it's a 4x4 configuration pickup. You replaced all the correct parts, using the correct fluids. If there were an engine system malfunction, then the computer would set a check engine light.

strong>Dear Doctor: I purchased a used 2014 Jeep Wrangler Unlimited Polar Edition several months ago with 21,000 miles. Recently, after starting the engine, the ABS light and the stability control lights came on. After pulling out of my driveway, the lights go out. But, when returning home and pulling into the driveway apron, these lights turn on again. Fortunately, I did buy an extended warranty for this vehicle. Any thoughts? Vinnie

strong>Dear Vinnie: The computer will hold the trouble code in memory, even when the lights are out. I would take a close look at the ABS sensor wire going to all wheels; it sounds to me like a wire connector, not a faulty ABS sensor. I see a lot of these Jeeps that have been raised up, or used for off-roading where the ABS wire has been stretched. Your technician will be able to identify the wheel that has the sensor fault.

strong>Dear Doctor: I own a 2009 Toyota Tacoma 2WD with the four-cylinder engine. For the past year the radio has been cutting out. Sometimes it comes back on immediately, and other times it takes a few minutes. The dealer said I may need a new radio, costing $1,200 plus labor. What would you do? Bill

strong>Dear Bill: I recommend installing a good aftermarket radio for one-quarter the price of a new radio. Today's aftermarket radios are plug-and-play units that include the wire adapters and radio face plates, which are capable of being controlled through the steering wheels controls, if applicable.

strong>Dear Doctor: My 1997 Ford Thunderbird has 191,000 miles. Since I last put gas in it (I always zero out the mileage counter), I've driven the car nearly 150 miles and the gas gauge hasn't moved below the "F" mark. Prior to this time I hadn't notice any issue with the gauge. What should I do? John

strong>Dear John: Most likely there is a problem with the float in the gas tank. The technician can try to read the fuel-level sender with the scan tool if the car has software, or check the actual OHM resistance and wire color at the tank. This information is available at Alldata and Identifix.

Why Does Engine Buck with Cold Weather?


Why Does Engine Buck with Cold Weather?

strong>Dear Doctor: We have a 2008 Chevy Malibu that has developed a cold-weather issue. It starts fine, but when the engine is cold and the outside temperatures are below 50 degrees the engine bucks or lurches when slowing for a stop. Sometimes it stalls, and the colder the weather, the worse the problem. Once the engine warms up, the problem goes away. The car seems to run okay otherwise. There are no trouble codes in the onboard computer. Fran

How to Jump-Start: Use a Battery Jump Box


How to Jump-Start: Use a Battery Jump Box

strong>Dear Doctor: I was asked to jump-start a friend's dead/weak battery from my 2015 Subaru Outback, but I said no, fearing it would damage my own battery. But later I read the owners manual and it indicated it would be okay to do so. What are your thoughts on jump-starting a battery from my own vehicle's battery? Jon

What is Proper Tire Pressure for Cold Weather?


What is Proper Tire Pressure for Cold Weather?

strong>Dear Doctor: I own a 2018 Chevy Cruze equipped with 17-inch aluminum wheels and the Tire Pressure Monitor, which is a great feature. The dealership told me to maintain 35 psi in all four tires, but I have noticed with colder weather now, the tire pressure has dropped off to the low 30s, and not every tire has same reading. Is this to be expected? James

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