The 3.5L V6 uses Honda's Variable Cylinder Management (VCM), switching between 3, 4, and 6 cylinders based on load. The cylinder transition vibration prematurely destroys the right-rear motor mount — typically by 80,000–100,000 miles. This is the same issue as on the Accord V6, but on a heavier vehicle with more total engine mass.
With the engine running in Drive, foot on brake, hood open: watch the engine for visible movement at idle. Minor vibration is normal; significant rocking or a visible gap in the right-rear mount = replacement needed. A mechanic on a lift can compress the mount by hand — it should resist firmly.
Est. cost: $400–$700 right-rear mount / $1,200+ if all mounts are affected
Source: Honda VCM motor mount pattern (shared with Accord V6)