It is a complete strip down and rebuild. I'm not an engineer but as long as you have common sense and a reasonable ammount of problem solving aptitude then it is possible. I removed the back panel and the top of the chasis to gain access. Be careful the wiring loom attatched to the back panel is quite restrictive. Though unplugging a couple of connectors will do the job enough to get the drum relocated. Small agile hands are required to re-connect the plugs whilst the drum is in situ. The belt will seem very very tight. I even thought I had the wrong one. But it does go. I did this on my own but would recommend 2 people.
I put the belt around the drum first and then locating the groove in the drum managed to get the belt over the pinion on the motor. I then struggled like mad to get the drum up to the door and located it whilst turning the drum as much as I could to get an even stretch over the belt.
Hope this helps, amateur Gav.
Wilson Chatting, December 2006