Car Talk

Q. My husband actually said this: “If you ask Click and Clack, and they say I did something wrong, I’ll stop doing it.” So here we go: When my husband backs my new Toyota minivan out of our driveway (he’s backing it down a hill), he doesn’t use the brakes. He just shifts it from reverse into drive as the minivan is still rolling backward, and then goes forward. I gasp when he does this, and he says, “What?” I tell him he’s going to ruin my transmission. He gives me a list of excuses why I shouldn’t worry about it. When he almost has me convinced, he says: “And by the way, I’m not even sure I did anything. But IF I DID, I’m sure it won’t hurt the car.” How’s that for covering his bases? But I think he made a crucial mistake in agreeing to abide by your decision. Give me some hope, guys! I need to know the correct answer, because my newly driving teenagers are often in the car with us, and I want them to learn to drive correctly.

TOM: Well, I’m less worried about your teenagers picking up bad driving habits than I am about them picking up some awful debating skills.

RAY: Yeah. I think “I didn’t do it, but IF I DID” tends to be a sure-fire loser in most marital disagreements, at least according to my brother’s four ex-wives.

TOM: And four different judges!

RAY: What he’s doing IS bad for the car. Cars can’t say “ouch.” But if they could, yours would be saying “ouch” and grabbing its transmission when your husband did that.

TOM: He’s using the transmission in a way it was never designed to be used — to stop the car. That’s what the brakes are for. And they tend to be cheaper than transmissions to replace.

RAY: While reversing directions without stopping the car first may not do a tremendous amount of harm if you’re going, say, half a mile an hour, if you’re backing downhill at several miles per hour and then change directions, you’re putting a serious load on the internal parts of the transmission.

TOM: And the damage isn’t confined to the transmission itself. Other parts of the drive train and suspension get jolted, too. Instead of being allowed to stop and start moving the other way, each part is suddenly slammed against the next part down the line. This leads to premature wear, and large outlays of money.

RAY: Here’s how you can demonstrate the concept to him. Next time you’re in the supermarket, let him go ahead of you, and then have him walk backward, at normal speed, to where you’re standing. Tell him that when you tap him on the shoulder, you want him to stop and then move forward.

TOM: Then, while he’s still walking backward, slam him in the tuchis with the grocery cart, hard enough so that he starts moving forward.

RAY: When he’s grabbing his backside and shouting: “Ow! What’d you do that for?” just say: “What? I didn’t do anything. But IF I DID, it might be a reminder to stop shifting from reverse to drive while the car’s still moving.”

Q. How does one tell the difference between a bad battery and a bad alternator? My car will not crank, but has some power (the dome lights, panel lights and power locks work). I’ve had it on a trickle charge for about a week. That has worked in the past when I’ve had a dead battery, but it still won’t start. Thanks for your help.

RAY: Well, it’s possible that the trickle charge isn’t working because your battery is dead and will no longer hold a sufficient charge.

TOM: But I wouldn’t rush out and buy a Diehard just yet, because that’s far from the only possibility.

RAY: Your battery could already BE completely charged. The car may not be cranking because you have a bad starter, a bad neutral safety switch, a bad clutch interlock (if it’s a stick shift) or even a bad connection from the battery to the starter.

TOM: So here’s what you do: Get someone to give you a jump-start. If you can get the car started with a jump, that suggests the battery is no good. Once you get it started, you can drive it to a local garage and ask them to test the battery for you. That will give you a definitive answer.

RAY: If you can’t jump-start the car, then you can be relatively sure that it’s a bad starter, or one of the other things we mentioned.

TOM: But if you’ve been charging it for a week and it still won’t start, that puts the alternator way down on the list of things I’d suspect. The alternator’s job is to charge the battery. And if the trickle charger can’t do it with the help of your power company, I think the alternator may be off the hook. Good luck.

Got a question about cars? Write to Click and Clack in care of this newspaper, or e-mail them by visiting the Car Talk Web site at www.cartalk.com.