Availability of the Moroso Lube has been spotty.
From our latest
assembly manual :
Differential: Fill with Moroso climbing gear lube, SAE 90, part number 34800, mixed with 4 to 8 oz. of Amalie limited slip additive (part # 505-6775). If the above are not available, you may use 80W-90 GL5 lubricant with an equivalent limited slip additive. If the limited slip seems to be sticking (ratcheting around sharp corners), drain and refill, replacing the Amalie additive with 2 tubes of GM additive 1052358.