Rear end howling noise

I've been ripping these threads up lately with my issues, but yall have been a lot of help. Anyway my 08 prerunner has started making a noticeable howling noise towards the rear. You can tell if you turn your ear in the direction. It is best heard for 45 to 60 mph and really does it is fairly inconsistently depending on the load. You give it gas it and will howl but sometimes it makes the noise stop. You decelerate and it does the same thing but over all its making a howling noise.

I have 2 leaks that I know of. My driver side wheel bearing and my pinion bearing seal. The fluid hasn't seemed to have gotten particularly low. Its probably lower than it should be but you can stick a screwdriver and definitely get a reasonable level without shoving it in really deep, giggity. It's dark but has viscosity if that even matters

I get a clunk when I give it a fair amount of throttle in reverse. Depending on what I'm towing I will get two chunks from the rear. One big one and one small one. I am doubting u-joints because I replaced them about a year ago.

I do pull some pretty hefty stuff as well and I'm drawn between the pinion bearing failing or my gears getting eaten up. I did change the fluid and looked at the magnet. I had what appeared to be one shaving and ground (powdered) metal.

Any input would be eternally appreciated.

 

When my 2009 started getting louder and then louder it was the entire rear rebuild time after the driveline shop looked at it - job was too big, hot, and messy for me so had the local guys do it. Yours could be driveshaft related also so check that out - center carrier and u-joints. I already had a newer 1 piece Tom Woods rear shaft so knew it was not that.

FYI at 115k miles they rebuilt rear end (pinon and carrier bearings), new rear wheel bearings (pressed on axles), new front wheel bearings (yes 1 was shot too so did both of course), new front driveshaft U-joints and balance (did not add much so did it as drive rough dirt roads at higher speeds in 4HI), and all diffs/transfer fluid changed for $1760. With your prerunner no front driveshaft or transfer of course but price was for all.

Well worth it to me and forgot how quiet/smooth the Tacoma could be.