I would put a thrust bearing in that pump before you use it again.  You have no idea of the history of that little bearings...and it when it blows up it can take a whole lot of expensive stuff down with it.

That being said, the chirping you hear very well might be what is refered to as "pump rattle"....it's a combination of spline slop and shaft vibrations from the thrust bearing not being loaded much under idle. 

If you've never done it and you don't know the history of it...yes.  Anything with moving parts that you buy used as an assembly should be looked at as a rebuildable core...nothing more than that...and certainly not a usable part.

Best to rebuild now while it's still functioning then wait till there's nothing rebuildable left.

Tom its a JB with an A impeller and it started at idle and we never reved over idle after that due to an engine oil leak just put it back on the trailer and hauled it home

got a bird somewhere in there lol