I need to service the rear axle on my Grand Marquis, and I've had zero luck with anything 75W, let alone 75W-90. The only one I've found was ACDelco Supreme Plus 75W-90, sourced from Delphi Belgium, but that was also out of stock. The GMC dealer instead had Genuine GM 75W-90 synthetic GL-5 available, which I just purchased for ~$16 a liter (I need 2L). It's got a nice scent to it, too...smells like grapes. Just wondering what base stock this comprises of though, anybody know? I think it's safe to assume Group III? Also, who's GM's supplier? It seems Fuchs is their supplier in Australia for their ACDelco range, but I haven't found anything about their US supplier. Could the Genuine GM stuff be sourced from a different supplier than ACDelco? Thanks!