Correct diff fluid for 05 Silverado
 

I am looking to change my fluid since I have 105K miles on this truck.

It is a 4.3 base model, std cab, 10 bolt diff.

Book says GM only for steerable rear axle (do they mean 4x4?) and 75w90 for non-steerable (which I think is what I have).

Am I good to replace the current fluid with Valvoline 75w90 full synthetic limited slip fluid, or should I use the non- limited slip, or something else?

Thanks ahead.