Do you need to remove the manual transmission from a 4X4 87 S10 blazer in order engine?

No, you generally do not need to remove the manual transmission from a 1987 S10 Blazer 4x4 to remove the engine. While it's connected, the transmission can usually be supported and moved out of the way to allow engine removal. You'll need to disconnect the driveshafts, clutch linkage, and various other components, but the transmission itself can typically remain in the vehicle.