OK Sammy, easy job in a difficult position to work in.
So I drain the fuel tank then remove the battery.
This allows the mower to be lifted from the front & sat on its bum so you can see everything and not eat grass.
This is what you have underneath, engine towards the bottom of the page.
http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt
Remove the tensioning spring ( 7 ) and idler pulleys ( 16 & 11 ).
these pulleys will most likely require replacement so you may as well do it now.
Being this is a Deere, the bolts are captive coach bolts but you might need to put your finger on the head to stop it slipping out of the square hole.
Check the two bushes ( 17 ) and again, I replace them purely because it is easy to do while everything is apart and they will be worn.
Just make sure you remove the pulleys first before you take the pivot bolt or you will need 5 hands to hold everything.
Loosen the belt guard ( 3 ) you can remove it if you like.
To get the belt off the tranny slip it between 2 blades then rotate the pulley.
The belt will just about fall off now.
While it is off, give the fan on the transmission a good check out, the splines get worn down and if they strip then the fan will not be able to cool properly.
Installation is as they all say the reverse and it will be a lot easier to do the fan pulley first.
Double check the belt is in all of the pulleys properly before you replace the spring.
Allow a couple of hours this being the first time you have done it.
