Don't use gear oil. It will leak.
Here's the steering box thread by Gary Ramadei from Digital Corvettes.
http://www.digitalcorvettes.com/foru...ad.php?t=76773
Lucas Red "N" Tacky and Marine Green were mentioned as good greases to use because they don't separate.
The GM 1051052 Steering Gear Lubricant is obsolete. They say not to use EP chassis grease.
Ford used Saginaw steering boxes too... My 1972 F250 uses Ford C3AZ-19578-A grease.
Here's the excerpt from the 1973 GM light truck service manual.
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Manual Steering Gear
The steering gear is factory-filled with steering gear
lubricant. Seasonal change of this lubricant should not
be performed and the housing should not be drained-no
lubrication is required for the life of the steering gear.
Every 36,000 miles, the gear should be inspected for seal
leakage (actual solid grease-not just oily film). If a seal is
replaced or the gear is overhauled, the gear housing
should be refilled with No.
1051052 (13 oz. container)
Steering Gear Lubricant which meets GM Specification
GM 4673-M, or its equivalent.
NOTE: Do not use EP Chassis Lube, which
meets GM Specification GM 6031-M, to
lubricate the gear. DO NOT OVER-FILL the
gear housing.
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