i'm getting this checked out today with my mechanic also.
80w90...with a diff additive for the rear
Only if the diff is locked
yes it is. to check look for the big diff in the rear axle. big diff? a large round metal casing.
If diff lock light is stuck on DO NOT DRIVE IT ON THE ROAD it will break. Ensure shifter is in diff lock off position and slowly drive forward and back in a straight line.
If it happens only when turning corners, this is likely to come from the differential. A ball bearing problem would make noise all the time.
your front diff is just about stuffed
Rear diff fluid
2 wheel or 4 wheel drive . front or rear ?
The third differential is more commonly known as the centre diff as its located on the transfer box. Older series land rovers were rear wheel drive until you engaged four wheel drive whereas the newer models that had a centre diff allowed 100% of the drive to go to either the front or rear axle depending on which one had the path of least resistance, when you engage 4 wheel drive you are locking the centre diff so it then transmits 50% of the drive to the front axle and 50% to the rear.
the tab should be on the diff
When the diff lock sticks make sure the diff lock lever is able to move freely. If so drive the tractor in 2nd gear with medium rpms. Sharply hit the brake while slightly turning the steering wheel and NOT touching the clutch. It might take a few times but the diff lock should pop out.
I have actually done this! it did not fix my problem. I had drive line noise. turns out it was the drive shaft u-joint. first drain the diff fluid to shed some weight. unplug the speedo. then disconnect the driveshaft at the diff, 4 bolts. then hold the diff up with a floor jack. remove 4 bolt from the top of the diff. and lastly the one bolt that is obvious. lower the diff. put the new one in reverse order. I have never seen a broken differencial from a BMW. these are very well made.