The 2.4 engine has a timing chain. The 3.0 engine has a timing belt, assuming the timing belt is what your asking about.
the best is to bring your belt to the parts store, since it takes only 1 minute to remove it (you even can remove it on the parking lot :-)
Yokohama, Michelin.
There is no need for a serpentine diagram for the 2001 xl7. Since it has two belts the only thing that you will need to remember is that on the power steering belt, the belt goes around the cranck shaft(Outer part of the cranck shaft, the alternator belt is installed prior to the power steering belt), the power steering pump and AC compressor. The flat part of the belt touches the flat part of the tensioners. Everything else is simple, the belt goes around the cranck shaft, fan and alternator.
You will need to loosen the tensioner pulley in order to create slack in the serpentine belt. The belt will come off with the tensioner pulley loose. Reverse the process to install the new serpentine belt.
The 2002 GMC Yukon-XL has a V8 engine.
The 2002 GMC Yukon-XL has 16 valves.
The 2002 GMC Yukon-XL has a 4-speed automatic.
The 2002 GMC Yukon-XL has overhead valves (OHV).
The 2002 GMC Yukon-XL is a gas-powered vehicle.
The 4.0 liter SOHC has ( 3 ) timing CHAINS and if it is 4x4 it has a 4th chain for the balance shaft
18 gallons.
The curb weight of the 2002 GMC Yukon-XL is 4947 lbs..