Today: Is Jackson's wife to blame for transmission problems?

Dear Car Talk

Dear Car Talk | Jun 01, 2011

Dear Tom and Ray:

Something my wife does drives me crazy, and I want to get your support before pointing it out to her. Our driveway is approximately 60 feet long and uphill. It's fairly steep for three-quarters of the run, then it flattens out at the top. My wife insists on backing up the driveway to park so she can go forward down the driveway in the morning. I think that backing up is harder on the transmission than driving up forward. Currently, we are experiencing signs of transmission issues on our 2004 Volvo XC90 T6, which I've found are common with this particular car. But could my wife be exacerbating the issue or causing it directly by backing up the driveway every evening? Thanks for your wise counsel. -- Jackson


TOM: I'm glad you wrote to us, Jackson. That way, we can stop you from humiliating yourself in front of your wife.

RAY: And instead allow you to humiliate yourself in front of the whole country.

TOM: It's unlikely that your wife had anything to do with your transmission problem -- unless she's backing up 60 miles a day instead of 60 feet.

RAY: In which case, she'd have a transmission problem and a stiff neck.

TOM: Reverse gear is basically the same as any other gear, in an automatic transmission, Jackson. In most cases, it's made of the same metal and uses the same hardening process. And in many automatics, reverse actually is not a separate gear. The transmission just uses an internal clutch or a brake to make one of the forward gears go backward.

RAY: Some manufacturers may choose to save a little money on their reverse gear by not making it quite so high-quality, or by not putting it through so rigorous a testing regimen. Why? Because it doesn't need to perform as well as the forward gears.

TOM: Right. Reverse never has to be "slammed into" at 6,000 rpm. It's always engaged at idle. And it never has to mesh perfectly at 5,000 rpm. Most people rarely go above 1,000 rpm or 2,000 rpm in reverse.

RAY: The vast majority of the time, reverse goes completely unused. When given a choice, most people prefer to go forward.

TOM: Compare the mileage you've driven in reverse with how far you've driven in the forward gears. You say your driveway is 60 feet long and your wife backs up it every evening. If she's done that 365 days a year since the car was new in 2004, she'll have gone a total of 29 miles in reverse by now. Compare that with how many forward miles you have on the car: 60,000? 90,000? 120,000?

RAY: So the use of reverse is almost insignificant in the life of the transmission.

TOM: What's much more significant is how hard you drive the car -- whether you stomp on the gas and do jackrabbit starts, and whether you shift from drive to reverse or vice versa while the car is still moving.

RAY: And probably most significant, in your case, are the design and manufacture of the transmission, and the match between the engine and transmission. We know Volvo has had trouble with the XC90 T6 transmission from your year, and I'm guessing it's because the transmission can't handle the torque that this turbocharged engine puts out.

TOM: So you should see if your Volvo dealer will take pity on you and help you fix this, Jackson. That's definitely the person to discuss this with, rather than your wife. Right now you've got a transmission problem. If you blame it on your wife, you'll have a transmission problem and a marital problem.

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