OMG....only 4 years old and 50K and there's Gearbox oil leaking on the drivers side and a whining in 4th and a bit in 6th gear...not a gearbox please...I bet a Scout gearbox is millions!......anybody come across this before!.

Get it checked, could save you in the long run, might just be a seal.

Gear/Haldex oil should be changed at 40,000 miles.

I am assuming it is up to date with servicing.

as in "drivers side drive shaft?"  sure it's oil and not joint grease?    easy to check levels and remember there are two at the front   each use different oil 

which may well mean the haldex hasn't been done