Probably the wrong Richard, however, if you refer to the diffs than its SAE140 gear oil to GL1 spec.

The use of EP or Hypoid gear oils will eat the bronze crown wheels of these worm drive diffs.

Its not uncommon to find these bolted-up bronze crown wheels missing, the REME museum example at Bordon here is just such, they obviously fetched a good price once upon a time with the scrap man; it is a big chunk of bronze.

Driving one axle of a CDSW is a bit of a disaster since the axle linkages have the effect of lifting the driving wheels and applying more down load to the non-driving set, not a problem when both axles are driven as it balances itself and aids cross-country mobility as designed, however with only one driven, a slight slope on wet grass can defeat it as I have witnessed.

R.