Suspension "clunk"

[Triathlete]

Alright, heres the problem...
When backing up, turning (both directions) and hitting the breaks I get a loud clunk that feels like its coming from the suspension. This has happened 3 times in the last 2 days but doesn't happen every time. Nothing is rubbing, CV boots are good, nothing is loose under there. I'm not sure if it is the front or rear. The only thing that has changed since this started was new tires (same as the ones that were on it). All lugs are tight.
Any ideas??????
I had my neighbor (mechanic) watch and listen but could not duplicate it when he was there.

[luz]

I had clunks under hard braking that went away when I lubed the joints.

[Triathlete]

Hmmmm, hasn't happened again. I hate phantom problems...never know what it was or when it might rear its head again!

[etlsport]

luz, where did you lube/what did you use? i get a clunk during take off after a hard brake

[luz]

I used Mobil One Synthetic grease. There are other posts in the forum that discuss lubing the joints, but it's really easy.

There are three spots where there is a nipple or zerk joint that you plug your grease gun into. One on each U Joint and one on the shaft. Park on a level surface and if you can't get to the nipples, move the VX up or down a foot to where the shaft rotates and you can access the nipples.

Just be sure to get a grease gun with flexible tubing because it's hard to get a good angle without it. You can plug into the zerks and squeeze new grease into the joints until the old grease oozes out. Wipe off the excess and you're good to go. But be advised that the one on the shaft takes a while to fill up if it's completely dry as mine was.

[Triathlete]

Now it started doing in while going forward also (to a lesser extent). I think I've narrowed it down to the rear end. Sounds like the LSD is engaging (the jerking feels like the right side). Is the left side the usual drive side until the LSD locks up? When I changed out the diff fluid with mobil1 I only put one bottle of additive in it. Tomorrow I'm going to get a second and add to it plus check the fluid level (although there are no signs of leakage). We'll see what happens. Got two weeks to figure it out before heading to Moab.