Hi Joey, per the instruction for installing a 48" deck with a parallel hitch the mule drive belt goes on the top pulley groove. I attached a manual see page 4
Glenn some deck have a 3 groove center pulley.
I don't think Joey has that newer style deck that you posted the manual for.
Joey .... please also ignore where someone stated to make sure your spring loaded cross-deck pulley tensioners are set right. Your old style deck doesn't have spring loaded cross-deck tensioners. It should just have bolt adjustable idler pulleys that should ride against the non-driving side of the belt .... ie ... the left belt tensioner should ride against the flat part of the left belt on the front. The right belt tensioner should ride against the flat part of the belt on the back. See drawing.
Edited by Glenn Ayers, June 20, 2015 - 08:43 PM.