Left-hand and right-hand are referenced from the point of view of the tractor operator.
The flat backside of the belt rides on flat idlers; the inside vee rides in v-idlers and pulleys.
These John Deere products use belt part number M74747 which is 104.72" long, 0.5" wide, HA section, 0.31" thick, 32 deg.
| Click photo to enlarge | Click photo to enlarge | |
 #1. Overall view |
Overall view of the drive belt layout (#1). The engine pulley is at the right and the transmission is off to the left. The parking brake latch handle (#2, yellow) and its associated spring (#2, blue) must be removed to change the belt. |  #2. Remove brake latch handle |
 #3. Brake latch spring |
The front end of the brake latch spring (#3, blue) attaches to the brake latch handle bolt and the back end hooks to a bracket on the frame (#3, yellow). Both steering tie rods must be disconnected (#4, blue) to loop the belt over the brake latch rod and around the steering shaft (#4, yellow). |  #4. Loop around steering shaft |
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 #5. Engine pulley |
Bring the front loop of the belt around the engine pulley and the v-idler next to it. Be sure the belt runs inside each of the belt guides (#5, blue). The front hook of the tensioning spring is at #5, yellow. The electric clutch locks into the post at #5, red to prevent the clutch from rotating. Loop the back end of the belt through the belt guides and around the transmission pulley (#6). |  #6. Tranny pulley |
 #7. Tension idlers |
The back end of the idler tensioning spring hooks into a notch on the backside of the idler arm (#7, red). Both belt guides must be removed. Set the parking brake to provide slack in the belt. Route the belt around the idlers; the flat backside of the belt rides on the flat idler; the belt vee rides in the v-idler. Note where the belt guides set into a hole in the idler arm (#7, blue) and a bracket on the frame (#7, yellow). The back end of the brake latch spring can be seen at #7, green. A notch on the electric clutch fits around the post extending from the engine pulley guide (#8, yellow) to prevent the clutch from spinning. |  #8. Electric clutch bracket |
 #9. Deere STX38 belt (yellow deck) diagram |
Deere STX30 and STX38 diagram (#9). John Deere STX38 yellow deck (#10). |  #10. STX38 yellow deck |