Drive shaft (propeller shaft) / u-joint noise??? My 2005 LX470 emits a low frequency wah wah wah humming noise. Could be tire noise (BFG KO2s), but it starts around 20MPH and is rotational with wheel speed until it blends in with road noise at highway speed. I just change wheel bearings / races- no change in the wah wah humming noise. Have moved the tires around; no change. 217K miles on truck and prop shaft / u-joints I believe are original. I’ve greased everything. No change. Tonight I crawled under it to check for play. Front u-joint on rear shaft maybe has a very very tiny amount of play, same on rear most u-joint. If I push up and pull down on rear shaft, I get a clunk. Sounds like clunk is in center of drive shaft or just rear of slip yoke. Also can see a bit of vertical movement in the flange off the back of the t-case. I plan to replace both prop shafts with new OEM, but am wondering if vertical movement (albeit slight) is acceptable in the flange on back of t-case. Front prop shaft has slight horizontal play- maybe at the t-case or diff flange- I’ll double check both this weekend and try to post some videos. Wondering if this kind of play would lead to a rotational wah wah wah wah humming noise? Any advice appreciated!
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