I used the Lubrication Engineer's 90w the change before my last one. I highly suggest it.

 

I only suggested 140 because Alabama gets hotter in the summer than Ontario does. I have a Eaton rear axle manual (I realize your axle is not an Eaton) and this is what they recommend for heavy truck axles

Below -10F SAE80

Up to 100F SAE90

Above 100F SAE140


It is also going to depend on the load the axle sees, if you tow heavy loads in hot weather then 140 will give you better lubrication than a 90.