To replace a transmission drive belt on a Cub Cadet LT1046 you need to remove the deck, preferably put the front wheels up on blocks or stands, unplug the PTO power (directly under the engine, which can be a pain ) You need a 5/8" socket to get the bolt out of the PTO pulley assy.(electric clutch). If you don't have an impact wrench take a spark plug out and push rope into the hole. This will bind the cylinder and keep the drive shaft from turning. Remove rope and replace plug when finished. Battery and/or spark plug wires should be removed for this process for safety.
The PTO may be stuck on there so you may want to tap it with a hammer and a block of wood carefully to release it. Loosen old belt from tensioner pulley. Lower engine pully on drive shaft, below pully "keys". It may be difficult to remove. Spray with "PB Blaster" or similar bolt loosener spray. Remove old belt from engine pulley first, transmission pulley last. Remember how belt goes around pulleys before doing so, make a diagram to help.You'll need to put the belt on the transmission pulley first then thread the belt up to the engine pulley. Thread your belt back through the pulleys and tensioner (make sure your spring is strong enough to tension the belt or buy a new one). The PTO pulley is "keyed" on the shaft. Replace bolt and washer. Torque bolt to 38-50 ft. lbs. using the rope meathod as described before. Put your deck back on and you're ready to mow again.Good luck!