CV Jint or Bearing?

[Alliance]

Replaced both IWEs and have checked for vacuum leaks (perfect long-term vacuum). Have what sounds like a partially engaged IWE that changes proportionally with speed, originating from LEFT FRONT. IWEs are not engaged in 2WD and are solidly engaged in 4WD, when checked idling on jack stands. Makes noise in 2WD and in 4WD (auto and high) modes. Differential fluid is full and clean. Noise momentarily QUITS when making turns to the LEFT at speed. Noise returns when turn lessens. 231k miles on truck. No clunk sounds when placed in drive or reverse. Bearing grease looked good when IWEs were replaced. CV Joint, bearing, diff gears? Any advice? TIA.