it's a really high pitch noise and it does it at a slow cost and it gets louder when i press on the gass pedel well driveing i took the rear end apart and the teeth are fine on the ring and pinion there are no metal shaveings in the old oil i put new oil into it and it went away for afew hours than came back but worse than before there was water in the old oil so i was wondering if it might be the bearings in there that are going bad if any one can plase enlightin me i would love that i'm new with my ranger i aint had it long i was a chevy man before but this ranger has made me a ford man so it's all new to me thanks again