Brake Noise I recently had the front driver side brake pad slip. I got the pads replaced and rotors resurfaced. There was then a squealing sound from the front driver side so I brought it back and the techs cleaned and greased the brakes but didn't solve problem so they ordered me OEM GM brake pads. The sqealing went away but now there is a pulsing grinding/moaning sound from that same brake at low speed light braking and no one can figure it out. What could it be?

Does the car have an anti-lock braking system? Could be that the wheel is sensing a brake lock when there is none and the pulsing is coming from the ABS motor activating, and the grinding/moaning sound is the ABS motor running. If you have never checked or used your ABS system, take your car out to a big, vacant lot or on a street where it is safe and you can get the street wet. Get going about 50 or so and, (after securing all the loose stuff in your car and trunk,) lock the brakes up. You will feel a pulsation in the brake pedal and hear a wierd, moaning noise. That is all perfectly normal. The pulsing is the ABS motor and related parts applying and releasing the brakes repeatedly at a high interval. This is what keeps the brakes from completely locking up and gives you the ability to steer and control the vehicle while jamming the brakes on fully. If your car doesn't have ABS, the caliper may be sticking in and the noise and vibration are from the pad being loose between the caliper and the rotor. Take the wheel off and watch the pads while you have someone else push the pedal. Have them push it VERY SLIGHTLY at first and see if it locks the rotor from turning by hand. If so, it is probably working correctly. If not, it should lock up before they feel much resistance in the brake pedal. Still, if not, the rotor is probably sticking because the dirt/grunge ring on the caliper piston probably isn't letting the caliper travel out far enough since the rotor was turned and the caliper has to make up for the extra space. This is probably not the issue since we are only talking about a few thousands of an inch, but still...
It is hard to diagnose using someone else's ears, but you might go by a brake shop and ask them to listen to it and see what it sounds like to them. If a brake shop can't answer your question, find another brake shop!