Perhaps it's NOT the grease. Remember that the faster the motor spins, the higher pitch the sound, so if you old motor was very slow, the motor was turning too slowly to make teh whine you're now hearing.

Bob

Does anyone know. I basically rebuilt the whole rear power window unit, mainly to replace the gearbox. I bought a used gearbox from CSI, cleaned out all of the old grease and repack with new grease (Moly graphite grease). The window works great now, but the gear box howl like a banshee. Anyone care to commence?