Blower Motor Sound Issue

Hey y'all,

So I've have ventured through many forums on this and other sites about the interior Blower Motor going bad in Tundras. I have a 2010 Rock Warrior.

I recently installed my second blower motor, after the first one I purchased made the same electric spinning sound (like a whine). I tested the second one by plugging it in and turning it on outside of the well...

...and it had the beautiful sound of air blowing, no whining sound at all.

HOWEVER, after I installed it, carefully and made sure it was set properly, the sound was there, but very faint. It usually gets noticeable on the highest setting then stays noticeable throughout all fan speed settings.

I've put my hands in every spot I can inside that fan well, seeing if I can find a leaf or chipped plastic, something, ANYTHING!

But nothing.

So what could it be? Again, it's not the new blower motor, when you removed it but leave it plugged in, it'll sooth a baby to sleep with its sound. But once installed, in all settings of the HVAC system, including cabin recirculation, it has a whining sound coming from seems to be the blower motor.

I was suggested to put vaseline around where it sets into the well, but that didn't work. I've made sure my screws are not too tight or too loose, and I replaced the cabin air filter (trust me, it needed it). I'm at a loss. Any ideas?

Thanks!