I need a diagram on how to replace the deck belt on a X320 lawn mower, 48" cut. Thank you!

There are two deck widths. See operators manual, no registration no fee downloads are available at the John Deere website.

https://techpubs.deere.com/en-US/Search/Equipment

Ented model number, select appropriate document by serial number range and region (North America / Export,etc.)

Just order it for the model number

265-529 Replacement Belt Scotts S1742 S1642 Sabre ...

https://www.amazon.ca > 265-529-Replacement-Scotts-...

265-529 Replacement Belt Scotts S1742 S1642 Sabre 1542hs 42" Cut Lawn Mower Deck: Amazon.ca: Home & Kitchen.

TadaMark Replancement Lawn Mower 42" Deck Belt for John ...

https://www.amazon.ca > TadaMark-Replancement-Scot...

Replaces OEM: John Deere: M124895; Fits Models: John Deere: Scotts S1742 and S1642; Sabre 1542HS, 1542GS, 1642HS, 1742HS and 1742GS with 42" ...

Scotts S1642 (Deck 42") Riding Lawn Mower ... - V-Belt Guys

https://www.vbeltguys.com > products > scotts-s1642-d...

Scotts S1642 (Deck 42") Riding Lawn Mower Replacement Belt ... My belts arrived when you said they would and fit perfectly. I would order again. ... This was our ... Rating: 5 · ‎6 reviews · ‎US$13.84 · ‎In stock

and more https://www.google.com/search?q=Scotts+s1642+deck+belt
..

HOW TO MAINTAIN JOHN DEERE LAWN MOWER DECK REPLACE BLADES PULLEYS BELTS

TRY THIS VIDEO MAYBE IT CAN GIVE YOU A BETTER IDEA .

Here's a link to your belt diagram. Service Mower

John Deere Ag New Equipment Technical Publications Equipment List

Maybe this diagram will be of some help.

http://www.bing.com/images/search?q=John+Deere+Tractor+Deck+Belt+Diagram&view=detail&id=FADA4E3096325222CAB37DCA483DFE884447BF4F&first=0&qpvt=John+Deere+Tractor+Deck+Belt+Diagram&FORM=IDFRIR

If you go to this page http://manuals.deere.com/cceomview/OMGX21647_K3/Output/Index.html?tM=HO , scroll down the left side to the heading for your deck.

http://www.askmehelpdesk.com/attachments/tools-power-equipment/21055d1245605830-sabre-38-deck-belt-routing-1438gsdeck.jpg

From the JD site, you can get the drive and deck belt diagrams here:

http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

***Don't forget to VOTE for the guys who take an interest in helping!