Talk Morgan Forums Thread Like Summary - 4/4 Limited Slip Diff Mystery

So I picked hp my second 4/4, a 2015 sigma engined model from a fellow TM member, and it's a wonderful car.

I noticed when I was cleaning the rebound spings and fitting new dampers that the original springs from factory were "Suplex", which I had thought was an upgrade.

On chatting to the previous owner, he suggested checking the diff, as he suspected it was an LSD. Lo and behold, it is a Limited Slip Differenetial.

On checking the build, no LSD is mentioned, previous owner thinks it may have been installed without him knowing and now seeing the Suplex suspension I wonder why Morgan would do this on what was to be a regular car.

Could it be they just were using what they had lying about, or maybe a cancelled order was changed to a new customer order and they just left the LSD and rebound springs in?

It handles great, so I just wondered if anyone would be able to shed some light on the parts.

Ran out of normal ones on chassis build day, or picked up the wrong one from the pallets behind after the tea break

As it happens I will shortly be replacing my diff oil. As I understand it LSD,s require an additive a friction modifier that in the past needed to be added to normal diff oil separately by the person changing the oil. According to GoMog if this is not done it would result in serious damage to a LSD within 1000 miles. This was the reason I contacted the dealers and MMC to try to establish which diff I had and what oil to use. As it turns out the oil the dealer uses is Castrol Transmax limited slip 75W-140. This oil already contains the additive but can also be used in none LSD axles so that is what I will be using.

Regards Tony

I used the same Redline 75W90 GL-5, which includes friction modifier, for my BTR cone type LSD axle. A lot easier than messing around with additives to old oil. It cured the clicking I got when maneovering on full lock with factory supplied oil. That was 25,000 miles ago. Recall having to buy another bottle as axle took more than volume quoted in handbook.