Does the label on the bottle of gear lube you used say it is compatible with limited slip differentials? A limited slip differential we call a Tracloc here in the U.S. (apparently Canada calls it a "Suregrip"?
) uses a clutch pack which requires a limited slip additive called a friction modifier.
Most gear lubes already contain that friction modifier additive but not all do. If it does contain the required additive, the back label (again) will say that it is compatible with limited slip differentials. If the label does not indicate that, you need to add 4 oz. of friction modifier additive that pretty much any auto parts store should carry. Don't add more than 4 oz. if the gear lube you used doesn't have the required additive.