Bought a new HF jack Pump Me Up Big Boy and maybe the third or forth time I used it, while raising the GX460 it was making some squealing sounds, almost like it was cavitating. Now I notice the first half of the stroke (pump handle vertical, down to about a 45deg angle) seems dead, like it's not moving any fluid. The second half of the stroke it will lift just fine. Think it's low on fluid or is there an issue? I just got it so I could return for another.