Stearing pump nnoise 1995 toyota tacoma

You may have air in the lines to the steering rack. or the fluid is low. there is also a chance your replacement pump is defective. a lot of steering pumps are remanufactured. a way to check for air in the lines is to take the filler cap off, have someone turn the steering wheel lock to lock a few times and hold for a few seconds at full lock each time, check to see if any air bubbles arise in pump reservoir. if no bubbles are seen you can also try a vacuum pull on the reservoir if you have the tool to do so, that tool will pull any air from the lines, but the engine has to be off because it will also pull some fluid from the pump in the process, when you don't see any air bubbles in the vacuum tools's lines it should be ok.