2004 Ford Explorer Eddie Bauer 4WD 4dr SUV (4.0L 6cyl 5A)
This car has always run rough - particularly the engine. Transmission had to be replaced when the car was less than a year old. The engine always had a loud whine on the highway and I had intermittent problems with the ABS light coming on and the 4x4 high light flashing. Turns out, this is all related and the entire rear differential needs to be replaced! A google search reveals that I am not alone. However, I am alone when it comes to paying the bill to fix this problem, apparently. I'd never buy this car again. Right now at 79,900 miles, but the whine has been going on for years. I just thought it was a loud truck.
Fix the rear differential problem. Make the drivers seat more comfortable.