For a 2001 Chevy Tahoe, it's
highly likely you'll need to drop the fuel tank to replace the fuel pump. While some access may be possible from the top, it's generally insufficient for comfortable and safe work. Dropping the tank provides much better access to the pump assembly and significantly reduces the risk of damage to fuel lines and other components. There's a lot less maneuvering and risk of spills.
While there are some anecdotal accounts online of people attempting it without dropping the tank, it's not a recommended procedure by mechanics due to the difficulty and increased risk of failure. Consider the time you'll save and the decreased chance of making a mistake by properly dropping the tank.
