Again, as long as the sector shaft is not worn, the bushings are tight, and the seal is tight, gear oil will work. 00 grade grease is equal to the old steering box grease GM used, it's much thicker then gear oil. A good compromise is 50/50 axle grease/gear oil. Just remember, there is no seal at the top of the gear box where the shaft enters, so don't tip the box over if you fill it before installing.
