Ok, so, weird one. GQ LWB rb30 4.3 diffs on 35's.

I've only had this happen twice. Once when flexing in mud, and once when driving up a hill covered in ice.

Basically, every now and then in these extreme low grip situations, I'll get a grinding noise and then sudden drive from the rear.

I haven't dumped the oil. At a guess, I'd say that I'm lifting a wheel or there is insufficient traction for the LSD, and it's basically turning itself into a single pegger. When the lifted wheel drops back down, or I get a bit of traction, I get the grind which I think is perhaps the clutch packs in the LSD grabbing again?

Has anyone experienced this? Any thoughts? Diff/car has only done 130k kms, and normally LSD's fine (like I said it's only happened twice).