Tranny/differential HELP

have a 96' 5speed manual 2wd 2.7l I4 all stock standard cab tacoma. It's been making this "clicking" sound for some time now around the rear passenger side, drums brakes are good, wheel bearing good (three different mechanics verified all of this beside myself), wheels good, not the hubcaps or a nail or brake parts or bearings or anything else I can think of. Midas said everything underneath looked better than most newer model cars. the only thing anyone can suggest is going to a transmission shop and having them tear into the differential and drivetrain. Anyone ever experience anything like this? It runs fine, no rough shifting or anything, doesn't sound like anygears are grinding or anything just that "clicking" that seems to follow wheel speed.

 

When was the last time you checked or changed the oil in your rear differential? I'd check the oil level.

When was the last time you lubricated your driveshafts? (u-joints, slip yoke, etc) I'd get the grease gun out lubricate and inspect them.