Rusty911
A2OC Donor
Seems to me from reading everything you have described is, sounding like its diff related. I have experienced the same symptom in another car. Worth spanner checking all the main bolts underneath. I experienced creaks from underload & breaking, never lateral forces, so used a breaker bar to check main bolts to get a true feel of how far tight they were done up, creak emerged, four bolt's got about a quarter turn.
Differentials can make you think something is loose / worn, but if everything else you have checked is fine, the diff is more than likely the culprit..?
Thank you. Could you clarify which four bolts you're highlighting? Like I say, I've tried all the usual wiggles, rotations etc etc with the car in the air and the diif feels fine as far as I can tell. I confess I didn't think to have someone hold the other wheel and have the car in gear whilst I did this: it might be doing that reveals some new noises. Trouble with this theory is the car does it going in (what is intended to be!) a straight line when the diff is not doing anything.
As far as I can see, as it's not a LSD, you'd need both one driveshaft to not get the drive to its wheel and the diff to be locked as well (otherwise you'd get no drive at all).