Defective bearings possibly due to leaking seal. Maybe able to replace bearing if motor is not damaged.
Filter pressure high?
Backwash sand filter several times.
If multiple backwashings don't help it maybe time to change the sand in the filter.
If you have a cartridge filter, then clean or replace cartridge.
If you have a D.E. filter, then remove grids, clean & recharge.
If there's a possible restriction in return line to the pool, then it could be either improperly adjusted or partially closed valve on return line.
Pump not pulling water/ not priming?
Loose strainer Lid
Defective strainer Lid gasket.
Air leak/ defective plumbing at pump Inlet.
Water level too low.
I found the parts cheaper Online can you match them?
This is a big one!!!
No. Here's why, the odds are, they have NO overhead because they are likely having everything drop-shipped from the manufacturer.
What about warranty? Do you have to send the defective one back before they'll send you a new one??
There has been a huge issue with counter-fit parts from overseas, we have encountered parts that have even fooled us. This was discovered the hard way when we had to replace Items like pump seals and filter cartridges the replacement items didn't fit & the customer had to buy a complete part again sometimes loosing hundreds of dollars with no recourse.
Last but, certainly not least, they all purchased from big online retailers. So, just be sure, "sometimes a cheap deal ain't a good deal.