My 2002 Ford Explorer (with about 85,000 miles on it) has what seems to be a peculiar transmission, transfer case, or traction-control module problem, but I?m not sure. The vehicle is equipped with an automatic transmission and all-wheel drive, but it can be manually shifted into locked, full-time four-wheel drive.
<br/> Here are the symptoms:
<br/> The vehicle behaves flawlessly when it?s cold, but after a warm-up of 5-10 miles of driving, a thumping-bumping-shuddering phenomenon occurs beneath the vehicle during acceleration after the transmission shifts into second gear. The problem persists after the vehicle shifts into third gear, but it?s subtler when the vehicle?s moving at a higher speeds. I CAN MAKE THE PROBLEM GO AWAY ENTIRELY BY MANUALLY SHIFTING INTO FULL-TIME FOUR-WHEEL DRIVE, but it?s inadvisable to drive around on dry roads in four-wheel drive, so that?s not a good solution.
<br/> Here?s the history:
<br/> The problem developed immediately after I went to a tire shop to get my four studded snow tires mounted and installed in early December. Halfway through the job the installer noted a cut through the bead on one tire?s sidewall, rendering the tire unusable. (Perhaps he himself made the cut while attempting to mount the tire on the rim, but I?ll never know.) The shop had no suitable tire to replace the damaged one, so the shop manager suggested that I leave the two already-installed studded tires on the rear of the vehicle, put my regular tires back on the front, and drive a mile or two to the next tire shop to try to obtain suitable replacement studded tires for the front. This strategy seemed reasonable to me, but as soon as I pulled out of the shop the thumping-bumping-shuddering phenomenon beneath the vehicle began. I thought perhaps a tire was way out of balance, so I turned around and drove right back to the shop. They put the vehicle on the hoist, checked the tires, and said nothing was wrong. So off I went again, thumping-bumping-shuddering down the road to the next tire shop. There, they advised me that it was a poor idea to put new studded tires on the front and keep my old studded tires on the rear, so they sold me a full set of new studded tires (about $700 worth) and off I drove with new rubber on all four wheels. The thumping-bumping-shuddering wasn?t as bad then, but the problem has never gone away. On the other hand, the problem hasn?t grown worse. Is it possible that by driving just a mile or two with a mismatched set of tires I damaged my transmission, transfer case, or traction-control module?