If you are just replacing the gasket you do not need to lift the engine. I have done it on both 2wd and 4wd trucks and it's not that hard. Last time I did it, I think it took an hour and a half.

If you need to replace the pump and pickup screen, then you will have to lift the motor. But since there is so much more work involved it's silly to replace those parts if they are working fine.