Originally Posted by Pompedo
On my 300x After 30 or so flights the motor locked up and caused a crash .. Horizon replaced the motor and skids and I had to buy the shaft ,spindle, main gear ... You have to clean and oil the motor regularly or else it will fail. I will buy a 450x
I'll bet the motor shaft toasted itself inside the lower bearing and that's why it locked up. The shaft wears down against the inner race and creates radial play which will eventually destroy the lower bearing. It's a known issue with these E-flite motors and you might just have the same problem with the 440 motor on the 450X. The fix is to disassemble the motor and locktite the shaft to the inner race of the lower bearing so the shaft doesn't spin inside the bearing respective to the inner race. 4503D motors were failing quite regularly when I bought mine. I did this fix and my motor is still running strong after hundreds and hundreds of flights. I did put in Boca ceramic bearings but, honestly, I think that was overkill and it had been flying just fine for many flights with just the locktite before I got overly paranoid about it. After I get a few more flights on my 450X to ensure reliability and that it doesn't have to be returned for anything, I'll just locktite my 450X motor shaft/bearing and call it good.
I wonder why Horizon replaced your motor and skids, but didn't replace the rest of the crashed parts. Replacing anything basically points to them admitting fault for the crash.