Dear Tom and Ray:

In a vehicle used to tow a travel trailer, if both were operated and maintained properly, which type of transmission would likely require the least repair: an automatic or manual? I plan to keep the tow vehicle approximately 200,000 miles. - FredRAY: Well, Fred, if you're planning to tow a travel trailer 200,000 miles with a manual transmission, make sure you also sign up for the "Clutch of the Month Club."

TOM: The thing about clutches, Fred, is that if the clutch pedal is all the way up or all the way down, nothing really wears out. The damage is done when the pedal is somewhere in between. So when you're starting from a dead stop, and letting out the clutch, those few seconds when the clutch is engaging are when 95 percent of the clutch wear takes place. That's when pieces of the clutch are rubbing together in an ancient and destructive clutch ritual we call "slipping."

RAY: The clutch HAS to slip in order to ease the car into motion without bucking and stalling. But the more weight you have in tow, the more slippage you need just to get off to a smooth start.

TOM: So an automatic transmission is what you want, Fred. Automatics use a fluid coupling instead of a dry, mechanic clutch. The fluid coupling is designed so automatics can slip almost to their hearts' content without doing any damage. That makes them the best choice for situations that call for lots of slippage, like towing a trailer or frequent stop-and-go driving.

RAY: And by the way, Fred, you should definitely get an optional "trailer towing package." That usually includes a heavy-duty transmission cooler, a more powerful battery and alternator, a set of rosary beads and a complete gardening catalog so you can quickly order replacements for all the flower beds you run over trying to back up this behemoth. Good luck, and send postcards.

Dear Tom and Ray:

What does the term "Quad 4" mean when speaking of automobile engines? - Scott

RAY: Quad 4 is a registered trademark of the General Motors Corporation. It's GM's name for a four-cylinder engine with four valves per cylinder, which is now a pretty common design.

TOM: Traditionally, each cylinder in the engine had two valves - one to let the fuel/air mixture into the cylinder and one to let the exhaust out after the explosion takes place.

RAY: But engineers figured out that if you used two intake valves and two exhaust valves per cylinder, everything goes in and out faster, and the engine produces more power. This technology has become cheap enough to use on normal, everyday cars.

TOM: And although General Motors was far from the first company to offer a four-valve-per-cylinder engine, they've demonstrated that they're still among the leaders in marketing jargon. They picked the name "Quad 4" because it harkens back to GM's glory days. It conjures up images of four-barrel carburetors, 400-cubic-inch engines, four-on-the-floor transmission, and 44 percent market shares.