Rear Diff lubricant & drainage advice please...

[Orkney]

Found 2l of Castrol EXP 80w-90 knocking about, leftovers from last tractor i guess.
Is this OK for rear diff?
Says on the container suitable for all manuals (ecluding LSD's) requiring API GLS Lubricants.
Meets or exceeds API GL5 or S cant read my own writing. Exceeds SAE 80w 90.

For some odd reason i'd never thought it was that sort of oil, thinking the tub was 5l of hydraulic oil or somesuch.
So is it ok to use?

If so best way to drain the existing please and fingers crossed it doesnt involve rear axle hub removal

[alex_holden]

There should be a drain plug on the bottom of the casing. I think it has a square hole that fits one of the socket wrench sizes.

[Willie]

Yes, the EP is the correct oil and yes, there is a drain plug at the bottom of the axle casing. Don't know which model you have but there can be problems if an earlier axle has been fitted with the later diff unit i.e.
there is no filler hole!!