Q: I have a question about servicing an automatic transmission. My maintenance schedule says to drain and replace the fluid at 120,000 miles. A friend in the business says this is crazy and that I should do this sooner. What is your take?
_ Alan B.
A: Renewing transmission fluid more regularly than 120,000 miles could certainly help extend the transmission's life. If one looks at the cost of a transmission rebuild, perhaps $3,000-$5,000 or more, to me it's a no-brainer to slip in some additional preventative maintenance.
A typical automatic transmission holds perhaps 12 to 15 quarts of fluid and a replaceable filter is often found within the oil pan. Removing the pan to drop the fluid and renew the filter is one way to service a transmission, but only 4 to 5 quarts of old fluid will be drained, the rest remains within the torque converter and other parts of the transmission. Another service method is to perform a flushing process. A fluid exchanging machine is connected via the transmission cooler lines and virtually all fluid is exchanged. This may require perhaps 20 or more quarts of fluid and doesn't address filter replacement. Combining the two services would be the ultimate solution, but isn't frequently done due to the cost. Some folks alternate between the two.
Were it my vehicle, I'd consider doing one or both of these procedures perhaps at 60,000 miles, or sooner if the vehicle is driven under demanding conditions.
Here's an idea for vehicles which incorporate a transmission drain plug (some don't have one): Perhaps at every third oil change, drop the 4 to 5 quarts of transmission fluid that is easily drained, and renew with the appropriate fluid. With new fluid gradually introduced, at least some benefits will accrue in a cost-effective and convenient manner.
Transmissions have evolved such that some require specific fluid qualities not found in multi-vehicle/generic transmission fluid. Manufacturer specified fluids or generic fluids that are licensed/meeting their specifications really should be used in many cases. For example Ford/Motorcraft offers nine different fluids depending on transmission type, including a special fluid for use in CVT (continuously variable) transmissions. Thanks to internet shopping, they sometimes aren't terribly more expensive than generic/multi-vehicle brands (many are about $7 to$15 per quart versus $4 to $6 per quart) while some fluids, say for the widely used eight speed ZF transmission can hit $30 to $40 per quart!
Q: My 2010 Ford Focus sometimes shudders when I'm accelerating. A friend connected a scanner and said I have a cylinder two misfire. Do you have suggestions of what to check?
_ Jenni S.
A: This may be an easy one! Your Focus employs individual ignition coils, one for each cylinder. They're inexpensive and easy to change, so I'd gamble $20 and renew the No. 2 coil _ it takes less than five minutes! (This is the second cylinder back from the front of the engine). If the scan tool is readily available, one can swap coils between cylinders and see if the misfire follows a particular coil.
