Purchased the 2003 Mercury, Mountaineer, AWD vehicle new on 6/17/03. On 05/10/06 at 50515, the left front hub bearing had to be replaced. A visual exam indicated water damage with bearing seizure. On 11/24/08 at 88826, the same problem as the earlier hub replacement was diagnosed. At this time both the left and right front bearing hubs had to be replaced. The right front hub was practically frozen and showed signs of heat fatigue to the outer casing. Both hubs showed rust and pitting. I maintained possession of both hubs for future reference. There is no doubt in my mind that had the hub locked up on the highway while traveling at highway speeds, (70mph) a potential for a rollover accident existed. On 11/21/06, a rear differential noise was diagnosed. The rear differential was rebuilt. On 11/24/08 the noise was again heard coming from the rear. Apparently the noise from the front bearings damage shielded the rear diff. Noise. I notice only one other complaint for the particular model year, however the basic drive train design has not changed for Mercury or Ford Explorer for some time and other model years may also have experienced this problem. There is no reason that a rear differential should not go 100000 plus miles without a problem and likewise there is no reason that the front hubs should not be able to roll up 100,000 miles without a problem. This is clearly a design flaw.

- Punta Gorda, FL, USA