My 99 4runner has started to slowly make noise in the rear end. As I accelerate it gets louder. and as I decelerate it gets quieter. If I take it out of gear and put it in neutral it makes the noise as well. I was guessing something to do with either the u joints or bearings. Not sure what to do next. All my fluids are topped off and nothing is leaking. I was assured it was not the tires. Please help.

 

check your u-joints... mine did this, it was u-joints... crawl underneath and shake the crap out of them by grabbing on to either side, shake/twist/etc, there should be no movement whatsoever, check both rear and double-cardan near tranny....

when mine were bad (just rear) there was just a little bit of movement in twisting. upon taking apart they were completely rusted and destroyed inside (the needle bearings). It was a 2hour fix for me once I got the right tools. I used a tie-rod end press thing, a BFH, a bench vise, and some sockets.

 

^^ X2 ^^