My Hayward Ecostar 2.7 ..8yers old...seems to be binding up... I tried to see if the impeller will move freely and I turned the rear Allen wrench nut and it is very difficult to turn..needed players to turn Allen wrench.. sounds gravelly when turning. Checked for blockage debris etc.-nothing. It ran for about 20 mins - opened pool today- and sounded louder than normal... and just shut down. Every once in awhile..the motor will turn on for a few seconds and then shut down.... after a few turns of Allen wrench You can physically hear it trying to start and then shuts down . FYI..Replaced Hayward drive unit 3 years ago.. was handy enough to put it in myself..Was having issues priming pump last season... would have to shut it off and then push resume button on drive... would get it going. Any ideas or comments would be appreciate. If I need a new pump.. which almost sure I do, I am reading that the Hayward Tristar 2.7n would be a better replacement. Am I reading correctly that the plumbing would line up and compatible with Pro Logic etc. ? If so... will try to do it myself. Thanks very much.... Any input/ guidance is appreciated.