I still get the rattling near the meridian. Its strange, because the rattling is not very consistent regarding its alt/az position. Some positions, the problem is minimal, some its very bad.

Here's what is baffling me. How can a gear drive that is barely turning produce a rattle with such frequency and amplitude? Does anyone know how fast the motor rotates at tracking speed? It seems to me that about the only thing that could cause this rattling at such slow speeds is a motor bearing, assuming the motor rotates at high RPM while tracking.

Regardless, it appears that repairing myself without voiding the warranty is out of the question.