A cursory look through a 2010 Challenger owner’s manual might land one on page 253 of Section 5, Starting and Operating. Right there under a great big “Caution!” header is a little ol’ bullet point that probably goes largely unnoticed: “Do not rest your hand on the shift lever while driving, as this may result in transmission synchronizer damage.” Most modern Challenger manuals will administer similar heed, but it’s important to realize that this same direction should apply to almost any row-your-own gear box.

If you don’t want to take Dodge’s word for it, then truck on over to Silver Sport Transmissions (SST) and see the real-life carnage that this bad habit can cause. According to a recent SST newsletter, a 6-speed Magnum’s trip to their shop in Rockford, Tennessee uncovered signs of this unknowing abuse that is easily explained.

“The weight of your hand on the shifter is enough to slide the synchronizer so that it is touching but not engaging the gear,” says SST. “The friction rounds out the gear teeth, causes the shift keys to wear, and the synchronizer ring is covered with hot spots. When the gear’s teeth are damaged, you may notice the transmission pop out of gear, grind going into gear, or be difficult to get into gear at all.”

So what’s a gear-grabbing gearhead supposed to do? Rather than resting that right hand on top of the T-handle, pistol grip, or shift ball of your choice, maybe just go ahead and give the old fashioned “10-and-2” approach a try.