The oil pan on my 1988 S-10 Chevy Pickup is rusted out. The manual says that the engine must be pulled to replace it. Looks like it may be possible to do it with the engine still in.
A few more details are always helpful. For instance: is your S-10 two or four wheel drive, and which engine are we working with, the 2.5L 4-cyl, the 2.8L V6 or the 4.3L V6? With the aid of the Alldata information system, and process of elimination, it looks like you're driving the two wheel drive Chevy "S" series with a 2.8L V6. All other engine and model combinations do not require engine removal to replace or reseal the oil pan.
The reason behind pulling the engine in order to remove and replace the oil pan properly is a lack of clearance at the crossmember, even with the engine unbolted at the motor mounts and jacked up as high as possible.
Many do attempt short cuts on this type of job, such as sneakily removing the oil pump with the pan unbolted from the engine block, or unbolting body mounts and actually lifting the body along with the engine to gain additional clearance. There are also those who simply attempt to forcefully pry the pan in and out which always results in a never-ending oil leak.
The best way to go is to remove the engine just like General Motors recommends. Very often the attempted short cuts end up costing you more time and effort, and/or makes it impossible to do the job correctly. That means you'll be doing it again.
It's also a good idea to replace the rear main oil seal while the engine is out. This is a common failure on a 2.8-liter with significant mileage. Besides, pulling the engine on this truck is a piece of cake.