Well, we went out yesterday and decided to tackle a place that we nailed the previous outing - well, the H3's nailed it the rest didn't.
Anyway... bit of a rock step climb preceded by a load of soft sand, 80% of the way up sounded like a machine gun went off underneath
... so backed off, and gently ran forward on some level ground - nasty clicking thumping noise coming from the left front
Couldn't see any leakage etc anywhere, but the noise got slightly worse so - called HUMMER Assistance and it went off to the dealer on a truck
Waiting for the dealer to get back to me today with the diagnosis
At a guess - best case, the left halfshaft has bitten the dust... worse case, the diff has binned it!
Cheers
JFF