The one that goes from the front all the way to the back is the drive or transmission belt.
It is up the top
the one that goes to the blades is the deck belt.
As for the exact routing, my JD data base only goes back as far as 1985 and there is no LTX 1040 in there
Rule of thumb is V pulleys have the V side of the belt in there and flat pulleys have the back of the belt running on them.
Don't forget that when you press the clutch/brake pedal down ( which you do to replace the belt ) the belt goes slack till you release the pedal again.
