My sister has a half-mile dirt driveway with humps to divert rainwater.
For at least a year I've been getting a nasty thud from the right
front if I cross a hump a little too fast and top out the suspension.

Now it thuds all along the driveway but not on pavement. There is oily
dirt sticking to the bottom of the right front strut and the surfaces
below. (The dirt looks oily but doesn't feel greasy.)

If I depress either front fender, it comes back up with no bounce. I
would have predicted bouncing from a defective strut.

I guess I need to replace the strut. I'd like to know why the fender
doesn't bounce and if the condition is dangerous.