gear oil you can buy it at any automotive store
The size of the front ring gear in a 1992 Chevy pickup is 7.5 inches. The 7.5-inch ring gear needs a 26 spline axle shaft.
You can refer to your user manual to ID the rear end gear ration in 80 Chevy pickup.
3.08
synthetic gear oil
SAE 75W90 synthetic gear oil.
75w90 synthetic gear oil.
Probably the steering gear.
I believe that is 3.50
4.10 ratio
80 or 85W90 gear oil.
footbrake deactivation switch
I am not positive about this but, I believe that this indicates that the axle has a 3.00:1 gear ratio. Check with you local Ford dealer for a definitive answer.