Originally Posted by BigLes
Originally Posted by RichardV6
You say you have changed diff oil several times but with what? You must use oil with LSD friction modifier included or add it to existing.

I changed the diff oil to Red Line 75W90 Fully Synthetic Gear / Differential Oil in April '25 at 10500 miles. This has since been changed to Morris Lodexol XFS 80W-140 in late June '26 at 13250 miles.

I haven't fully checked the specs above BUT I think only the Morris is LS, it's vital you use a high grade LS (limited slip) spec oil in a Roadster as the friction of the plates / cones within the diff depend on it

Jon M