Had front disc brakes changed a few days later when I stop slowly the truck pulls to right with a pulsing/purging sound thru the vehicle. When I make a fast stop this does not pull to the right also no pulsing or purging sound.
Did the brake job include new rotors? Or, did they resurface the rotors? It seems you have either a defective new rotor, or a resurfaced rotor that has warped.
Sometimes resurfacing a rotor can make it so thin that it can warp. If you got new rotors, one of the new ones is bad and the shop should replace it. If they resurfaced the rotors, it looks like you need to replace them with new ones.
Maybe a caliper is binding. Would you feel confident that you could remove and inspect the front calipers and pads?
Can they be greased or do they need to be replaced (The Calipers)
If a caliper is sticking because of the slides then yes, those can be greased and should have been when the brakes were done. If the piston itself is sticking then, no. You replace the caliper.
Another thing to worry about is the flexible brake lines in the front. The interior walls of those can break down and create havoc with the brake line pressures.