So when I start my truck and put it in reverse and dont let off the brakes or rolling with a little bit of gas, theres a weird sound that comes from my drivers side... it kinda sounds like my abs kicking in... aswell at low speeds coming to a stop my abs does kick in, and usually turns on my abs light and then quits... I dont get any codes. I have a 99 f150 7700 with a 5.4 and 194xxx km

 

Check/clean your wheel speed sensors. Also check the wires for chaffing.

 

Change your brake fluid and bleed lines.

 

Will do! Why the brake fluid though?

 

There might be some air or the brake fluid is old, a lot of moisture build up.

I had same noise after I changed the fluid no more noise and my brakes stop so much better now.

bleed till you see new fluid do it in this order RR,LR,RF,LF.