per GM bulletin #PIT3384
It may be noticed that the shocks are weeping oil on full-size pickups and utilities, especially if exposed to cold weather. This condition usually occurs when the vehicle is raised on a hoist that does not support the wheels. In these instances, it would be prudent to first drive the vehicle and exercise the shocks prior to hoisting the vehicle. It should be noted that this "weepage" is a normal characteristic and does not adversely affect shock performance and shock replacement is not necessary.