NTH

Yes GXs are AWD.
Vehicle is actually super smooth and stable on stands under rear axle and front frame and 2 additional jacks under A Arms just enough to relieve angle. Check out Esco stands. There’s options for axle and flat tops for the frame. It’s the only way to rule out third member/pinion noise.

BzzrBeater

These are all good points. I did get the trans fluid changed back when I purchased the vehicle in November. Since then, I’ve learned there’s a difference between draining and refilling and flushing the fluid. I’m unsure which was performed. I’m also unsure if there was metal in the fluid. Wish I had a space to perform this maintenance on my own but until I have a garage I have to use a shop. Next time I’ll be sure to ask for pictures of the fluid.

I’m fairly sure the vehicle was never used for towing, so I doubt the gears are in bad shape. I did schedule a replacement of the pinion bearing, but perhaps I’ll ask if they actually ran the vehicle at 60 mph on the lift before I go through with it. The tech seemed pretty convincing. He’s seen these bearings go bad on several 4Runners, including his own (which resulted in it completely failing when he towed a boat). According to him it results from a bad diff design by Toyota, where the oil does not get circulated well enough to the pinion bearing.

Lexus4321

If you re-grease the U and slip joints well, does the noise change at all?