I recently rebuilt the pump bearings on my X2. Old Skat 47V impeller looks good. I don't see rubbing on housing. The tail end of drive shaft that has splines fits into impeller has some play. Could this be where my rattle is coming from? I don't have a rubber seal around shaft and impeller but doubt that would help but only to hold some grease on splines. I tried packing grease into cavity to grease spines but no luck. This sound is out of water. Should I be worried?