The bolt for the rear guide is behind the right rear wheel, on top of the frame. You may have to pull the steering column, because on some JD's the belt runs on both sides of the column.
I did this job today.......
I pulled the steering wheel and pulled the engine bolts holding to frame out along with the exhaust cover in front. This allowed me to pull the engine up and slide it back just a little.
The guide (stud) on top of transmission uses a 6mm hex driver. Was able to put a small 3/8 inch ratchet on it.
The only pulleys I pulled were the idlers close to the steering wheel gear.
While I was at it, I replaced the steering gear and replaced the idlers since they appear to be worn and failure prone.
Got the parts at
John Deere Parts Online Discount Store: Green Farm Parts. Part #'s can be found on John Deer Website.
GX20006 John Deere Traction Drive Belt 1 $20.98 $20.98
GX20053 John Deere Gear 1 $35.66 $35.66
B30963 John Deere Lock Nut 1 $1.52 $1.52
GX20287 John Deere Idler 1 $7.21 $7.21
GX20286 John Deere Idler 1 $6.26 $6.26
14M7400 John Deere Lock Nut 2 $1.20 $2.40
GX21794 John Deere Stud 1 $14.61 $14.61