The lift system is likely a Goshen 2660 if the 4 lift posts are rectangular. Basically there is a compound system in the main tube in the bottom that the cable drives to shove 4 long springs up into the 4 tubes and into the roof to raise it. goshenstamping.com has a detailed version of how to perform repairs. Link is below. In their version it is performed with the roof closed but you might get by with the roof up a bit. To get it down, if need be, have 4 strong people at the corners use the palms of their hands to lift, and support the roof and remove the blocking, then lower in unison keeping fingers clear.
On separate note there are hydraulic ram and power winch systems available for raise/lower and this would be an ideal time to install one. I have the power winch and love it. up and down in seconds with no effort.
You should be able to order the cable through your dealer or contact Goshen Stamping directly. They have a website, email, phone, and fax all available online.