you should check the front anti-sway bar bushings, if that dont work check all ball joints , tie rod end's and stering knuckles if that don't get it check your wheel bearings. I have a '91 Ford explorer and I had that problem. I forget the layout of a '98's suspension but anyways, the problem was the bushings for where the radius arms go into a frame cross beam. (The radius arms run front to back).
Worn out front sway bar links or bushings can do that.
Worn suspension parts - struts Loose strut mount?
Possibly the sway bar bushings?
Could be the front wishbone. Mine was making similar noise, especially over bumps. Not a major repair - approx €250 euro
Worn out front shocks and struts will make a clunking noise when you go over small box. The strut may actually allows the tire to hit the fender well.
Bad Struts
I had this too and found the answer today...apparently LINK PINS!
The defective sway bar link can cause the clunking or the rattling of the noise from the front suspension during the low speed driving.
It's either something loose or something worn out. I'd start with the shocks then look at the ball joints.
sounds like the right front motor mount .i replaced mine and the clunking sound went away
Bad strut? Bad strut mount?
A clunking noise, when you put your car into gear, is most likely caused by a bad u-joint. A problem in the transmission can also cause the noise.