Up front the strut top mounts have a bearing plate. I believe this is what he is referring to.
Did it start after you had the axles replaced? If so it is probably a ball joint. The mechanic or yourself would have needed to seperate the ball joint from the control arm to get the axle out. It could have gotten damaged in the process. However broken ball joints don't normally show their faces until you get going a little faster. With that you would feel a lot of steering wheel shake and front end vibration. As well as some pretty good clunking as you turn while at speed.
Another area to look at are the wheel bearings up front. If they blow out you can get symptoms anywhere from a slight chirping squeek at lower speeds to a full on rhythmic grind.
Take it to a Tires Plus if you have one in your area. They do diagnostic and appraisals for $20.