axel hub nut is 30 mm
in the axle
185 to 260 ft lbs this is the front center nut that holds axle and front wheel bearing together not wheel lug nuts
Over the rear axle
Should be a 35mm.
You can find a 1989 Chevy front axle diagram at most Chevrolet dealerships. Most local libraries will have Chevrolet service manuals with the front axle diagram.
147 foot pounds
That switch is screewed into the top of the transfur case that's bolted to the rear of the transmission.
Under the motor running parallel to the front axle. It is round about the size of a small coffee can.
It is located right above the rear axle.
Please clarify your question as in front or rear axle.