Would you please listen to this video made right next to the pump in the rear wheel well. Notice the lower change in pitch of the pump at 20 seconds into it. After a few seconds it goes back to a higher pitch. Sounds like its screetching instead of whirring. Let me know what you think.
[video=youtube;geL0hEnoA5c]https://www.youtube.com/watch?v=geL0hEnoA5c&feature=youtube_gdata_player[/video]
[video=youtube;geL0hEnoA5c]https://www.youtube.com/watch?v=geL0hEnoA5c&feature=youtube_gdata_player[/video]