I have an ADCO for my 3600. The 37'-40' is too tight. I got the 40'-43' and it fits. Part #34858. Only problem is when the wind gets really blowing the rain spouts have managed to poke holes through the fabric or the spouts have broken. Also the metal trim around the tires has done the same, tearing the fabric. I don't use it any more as it's a pain to put on and then it rips apart when the wind blows. It has special straps but those don't work.
2014 Voltage 3600
2013 Chevy 3500 CC DRW
2011 Harley Ultra Limited 2016 RZR 900