Small Engines (Lawn Mowers, etc.): Craftsman riding mower slipping, belt tension, forward gear

Question
My Craftsman 12hp 38" cut riding mower model#  917.254240 seems to be slipping.  Whenever its in any forward gear under a load, such as going uphill, loud popping and loss of power occurs.  I thought maybe the belt did'nt have enough tension but after removing the mowing deck, I did'nt see anything to adjust.  I'm not sure how old the belt is could I possibly just need a new belt?

Answer
Owner's Manaual part number 109496X.

The loud popping noise may indicate transmission problems.  Does the transmission pop in every gear?  Reverse?

When you depress the clutch you will see the clutch idler pulley move.  The pulley is held on by a bolt.  Loosening the nut should allow you to slide the pulley to adjust belt tension.

You have a Peerless transmission.  Can you send me the transmission model number.  Some models are prone to certain parts failing.

The link below will help you locate the transmisson model number.

http://www.smallcarplans.com/manual.pdf

Let me know the transmission model number.
Eric