Clunking drivetrain

[dbgrubbs]

Picked up a 1990 vert a few months ago. Has 130K miles on it and was used sparingly by the previous owner the last 5 years. It's a 5 speed with a 3.73 LSD. I'm having some problems with drivetrain noise. I get a lot of clunking when engaging or disengaging the clutch and even more when under power going around turns. At times it almost sounds like rocks in a coffee can being spun around. It's so bad that I can feel vibration in the cabin. The sound disappears when cruising in a straight line. In my mind the culprits can be:

1) driveshaft u joint at the differential
2) differential going bad (has fresh fluid with no change)
3) axle going bad
4) wheel bearing

I've jacked up the rear end and rotated everything but the only noise I can get is from either the u joint or differential but doesn't seem bad at all. Maybe because there's no load on it. The guibo at the front seems to be fine as does the driveshaft bearing.

Can I get some opinions or past experiences on this before I start tearing things apart?

Thanks

[Jaxx_]

does the angle of a turn make a difference? For example, is it worse on a tight turn vs a long sweeper on the highway? what about direction? Does it sound worse or better going left or right?


I would be leaning to differential. What fluid did you replace it with? And clunking wouldn't be fixed with fluid if it is out of spec gear lash. "Rocks in a coffee can" I would hope is an extreme description, as an example, LSD clutches usually sound more like wood sliding against pavement.

[dbgrubbs]

I put redline in the diff but it was making the noise before too. It's just gotten worse in the past 2 weeks.

The harder the turn the worse the sound. Gentle sweepers and I don't hear anything. But drive it in a parking lot and it gets pretty loud. The noise changes with the degree of turn. A hard turn and it sounds like rocks swirling in a coffee can. A lesser turn and it's minor knocking. Doesn't seem to matter too much left or right.

[jonnywadster]

Did you figure it out? Wheel bearing or something in the driveshaft? possibly the diff?

Well let us know either way :)