I'm new to Ford, having just purchased a 2000 Expy 5.4 XLT w/75K, and have noticed a humming during slow speed turns 90 degrees right or left. It continues for a little while after I straighten out. I also have noticed the truck grabs (for lack of a better word) while making a hard right or left going forward but most especially going in reverse, and sometimes I need to gun it just to get it moving again (not what I look forward to doing in a parking lot!). This happens in A4WD on dry pavement and to a much less extent on snow and ice. I first thought that the truck was stuck in 4WD (my Cherokee acts the same way in 4x4 on dry pavement), so I took the fuse out but it didn't make a difference. Then I had the transfer case fluid changed out plus both rear and front differentials. Still no difference.

Is this sound and feeling normal?

Thanks for any advice!

 

I got a 2004 with exactly the same symptoms. In my case, it is normal. The cause is the very strong limited slip rear differential. If your car has a limited slip, during turns, it likes to go straight, especially during acceleration. That the reason for the noises you hear. The weird thing is that no two cars are the same; some have stronger clutch packs then others. So the noise is actually a sign, that your clutch plates in the limited slip are strong.

 

It's probably not your LS. It is most likely the A4WD engaging. The way that the center diff works is by sensing differences in the rotation speed of the front and rear drive shafts. So when you turn sharp the front drive turns faster than the rear and hence it locks or engages the A4WD and as a result you get binding. It is really nothing to worry about, however I am glad they put back in the 2WD switch in the '03's.

Best of luck and enjoy the truck.

 

The problem is the clutch packs in the rear differential need replacing. I am a service tech at Ford, there is a TSB on this concern because this IS NOT normal and IS NOT a good thing. I have replaced several in the 03s, cured the noise, and yes the 4WD still works as it should.