Piston Slap: Beached Shark, Broken Diagnostic Tree?

TTAC reader Tiburon Guy writes:

Hey Sajeev: Long time reader, first time e-mailer. I have a 2001 Hyundai Tiburon that I inherited from my wife when we got married (dowrys are making a comeback!). It has 70,000 original miles and I’ve maintained it properly. Recently a problem arose that the dealer could not point out nor could my personal mechanic (ASC Certified) determine the cause or solution to.

It’s an automatic transmission. Sometimes when starting the car, pushing the release button on the shifter is downright impossible. It’s stuck and won’t engage, which means I can’t shift into gear. After a few moments of wiggling and pushing and jerking (and crying on my wife’s part) it will give and we’ll be on our way.

This doesn’t happen all the time though, it’s once every month or so. Any idea what could cause this and if so, what can I do to fix or prevent it from occurring? We are the only owners of the car and have not raced or abused it. I’ve hunted the forums on the Hyundai fan sites and I can’t find anyone with the same issue.

Sajeev writes:

These brake-shift interlocks are a simple design: you push the brake pedal, the brake switch takes note, then a solenoid on the shifter releases it’s grip and you move out of park. And a competent wrench should find the offending part rather quickly.

The brake switch is simple, check if the brake lights illuminate when you touch the pedal. There’s probably a fuse, so the owner’s manual has you covered. Test the solenoid with a factory service manual (on-line or on paper) or pull it out of the shifter and stick 12v of juice at it. And removing the shifter might be a good way to check for binding in its mechanism. Let’s assume (hope?) this diagnostic tree was followed.

But if everything passed muster, perhaps the parking spot is the problem? Many cars are harder to move from park with a transmission “loaded” by the forces of an uphill parking space. And sometimes the transmission makes a terrible sound when the shifter finally moves out of park. The only solution is to engage the parking brake before going into park. And reverse the operation when you return: start the car, put the autobox in neutral or in gear, and release the parking brake.

More to the point, I suspect you can Cliff’s Notes my writing, post it on a Hyundai enthusiast forum and get a straight answer in a matter of hours. That’s my ultimate recommendation.

Bonus! A Piston Slap Nugget of Wisdom:

There is significant mechanical waste in modern cars, items that neither improve the driving experience nor make the car any safer. I suspect failed brake interlocks cause more stranded motorists, grey hairs, and unnecessary repairs than any potential lives saved from accidentally hitting the wrong foot pedal after start up.

Plus, the extra dollars added to a car’s MSRP are better spent on a fancy dinner with that special someone. And with that, I’d like to thank 60 Minutes for giving us this electrical pain in the ass, and make the obligatory hyperlink to Paul Niedermeyer’s excellent article on the Audi 5000.

(Send your queries to mehta@ttac.com)