Recently, I've been hearing a rather conspicuous whine coming from the rear of my 99 wrangler. I hear it at all speeds: whether accelerating, coasting or decelerating. It seems loudest when I take my foot of the gas. I took it to get checked out and was told I had a bad rear differential. They estimated as much as $2k to repair it depending on the number of bad parts etc. That's when I became a mechanic.
So far, I've replaced spider gears, two of which had pitted teeth, but this did not solve the problem. My wheel bearings roll smoothly and my carrier bearings seem okay (to me that is). So today I bought a dial indicator and measured the backlash. I see .017". (is that too much?) I then pulled the carrier and disconnected the drive shaft. I find no play between the differential case and the pinion shaft. However, when I spin the yoke, it doesn't spin as smoothly as I expect it should. I then started the engine and put it in gear (perhaps not advisable but I wanted to see if I heard anything) and engaged the clutch. Then I could really hear some chatter - not loud but enough to really make me suspect the pinion bearings (more than one in there right?).
So does it sound like I'm on the right track?