Belt diagram for a toro pro line 616-z - Toro Lawn Mower With Toro Power Tools

http://www.partstree.com/parts/toro/mowers-zero-turn-lawn-mower/74631-toro-timecutter-ss-5000-zero-turn-mower-sn-314000001-314999999-2014/belt-and-pulley-assembly/

Give this link a try. Once you have the belt diagram, and the right belt, it has to fit.

www.toro.com/en-us/customer-support/pages/default.aspx

check the deck carefully it might be written on the right side

Go to Partstree,com type in the Model number, then look in the diagrams. If you are looking at the PTO/Hydro Drive assembly then go here:
http://www.partstree.com/parts/?lc=toro_commercial&mn=74805%2C+Z355+Z+Master%2C+w%2F48%22+Mower+and+Bag%2C+2001+%28SN+210000001-210999999%29&dn=3326-242-_2420014-00012

belt guides need to be removed and the tensioner needs to be pulled in to give you the slack to get the belt on.
the belt guides will need to be put back in place

http://www.toro.com/en-us/customer-support/pages/default.aspx

manuals http://www.toro.com/en-us/customer-support/pages/default.aspx

Choose an operator manual or a service manual from this page. I'm sure a belt diagram is there.
http://www.toro.com/en-us/Professional-Contractor/Mowers/Commercial-Zero-Turn-Mowers/Pages/Model.aspx?pid=74296

THIS IS THE WEBSITE FOR THE MANUAL. SO FAR THIS IS THE ONLY SITE I HAVE FOUND WITH THE INFORMATION.

https://homeownersolutions.toro.com/portal/server.pt?space=CommunityPage&cached=true&parentname=CommunityPage&parentid=1&in_hi_userid=19462&control=SetCommunity&CommunityID=214&PageID=238#manualsResultPage

I HOPE THIS HELPS IF NOT PLEASE LET ME KNOW AND I WILL FIND SOMETHING BETTER.

For removing/replacing the deck belt, the general method is:

1. turn off engine, remove key and set parking brake
2. disengage blade by putting blade engage lever into off (disengaged) position
3. lower the cutting deck to the lowest position (closest to the ground)
4. relieve the belt tension (depending on the model, use a 3/8 inch ratchet set to tighten in the square hole of the idler bracket)
5. remove and replace the belt

NOTE: it's not necessary to completely remove the cutting deck.

Useful diagrams for removing the cutting deck, http://216.213.143.2/ProAuthor/ManProc.cfm?ManualID=425&ProcID=14794

For deck belt diagrams, http://216.213.143.2/ProAuthor/ManProc.cfm?ManualID=425&ProcID=14796

If the transmission drive belt needs to be replaced, several components must be removed and special tools (i.e. air/impact wrench) used in order to change the tractor's transmission drive belt. See an Authorized Toro Service Dealer to have your drive belt replaced.