Andrew bibby
Member
can you use 75 90 synthetic oil in the diff of a Discovery 3
discool
Well-Known Member
Comma oil recommend 75 90 semi-synthetic GL5 grade in both axel diffs.
sierrafery
Well-Known Member
You can use what oil you want but the best is to use what the builder recommends or something with the same specs not what oil sellers are advertising, here's from topix:
