2003 Explorer thumping upon accelleration.
I bought a 2003 EB Explorer 4X4 in July, with about 34,000 miles on it.
On a road trip, I noticed a vibration beginning, only noticeable at
65-70 MPH. I took a look underneath and only noted a slight leak from
one of the shaft seals (between the rear differential and the left
wheel). I took it to a service station, where they said the leak was
minor and the differential had plenty of oil. They balanced the
wheels, but the problem didn't really improve. They insisted that the
vehicle would be OK until I got home from vacation.
So, once back to Ohio, I took the truck to the dealer (still under
36,000 miles, luckily). They replaced the gears in the rear
differential as well as the seal (I now find that the diffential is a
common problem with the 2002-2005 models). The problem was somewhat
better, but not entirely. The problem was still manifesting itself as
a thump while coasting at highway speed.
So, I took the truck for a second visit to the dealer, where they
insisted that I needed four new tires (not covered by warranty -
imagine that!). I told the dealer that was BS, and they instead
rotated the tires and did a 4-wheel alignment. The problem wasn't
solved, but the symptoms changed to a thump during low-speed
accelleration. This change led me to believe there may be some
validity to the tires claim, but two were nearly new, so I got the
other two changed at the local tire shop. With the new tires and four
freshly balanced wheels, the problem was worse than ever, so I asked
the tire shop what they thought. They drove it, and said "No way is
that caused by tires - It's definitely a drivetrain issue".
The posts here have several entries about differential whines, but has
anyone experienced this thumping on accelleration? It almost feels
like hitting a pothole or seam in the pvement. Though it is
repetitive, it doesn't have a set rythm. For example, the thumps
aren't closer together as speed increases, and there are sometimes
longer pauses between them than others. My best guess at this point is
that the differential is binding up, or a U-joint / cv joint (whatever
they are calling them on the rear halfshafts) is bad.
Any ideas? I hope i can get my money's worth out of this, my seventh
(and probably LAST) Ford.