Lurker52,
If it's on a W-22 chassis, then it DOES have an Allison 1000 transmission.
Understand that a 2004 RV model might possibly be on a 2003 W-22 chassis due to the production cycle/model years of the manufacturer. That information should be on a sticker near the driver's door, if it has one. That's where it is on our rig.
Chassis improvements were quite frequent during that time as Ford and Workhorse were in a pretty good competition for "best chassis". In early 2004 (maybe March or April) for instance, Workhorse improved the wheel-cut angle and 2 other things, but the specifics escape me at the moment. So when we ordered ours, I made sure to specify the "newer" chassis. Obviously, you don't have that luxury with a used unit. In my opinion, during that time, the Workhorse was a better chassis than the Ford anyway. The WH had a lower "doghouse", for one, making access to the driver & passenger seats a bit easier. PLUS the Allison transmission. The WH chassis, depending upon the motorhome manufacturer, came with a price premium of between roughly $3k-$5k over a comparable motorhome on the F-53 chassis.
The floorplan of that rig is probably comparable to ours weight-wise, but from what I remember, the Tiffin units seemed to weigh-in a bit heavier than some other manufacturers. Our rig weighs about 18,800 lbs. empty, with only full gasoline & propane. So I'm guessing that one, being about 6" longer might weigh in 19,000-19,500 lbs. depending upon how it's equipped. Ours is also a dual slide. So you probably have about 2,500-3,000 lbs. capacity for food, water, people & stuff.
Fill the water tank and you eat up about 700 pounds of that.
As for towing, the GCWR for that chassis is 26,000 lbs., meaning that IF you load the rig to it's maximum 22,000 lbs of GVWR, you can only tow 4,000 lbs. (26k-22k=4k), assuming it has a 5k tow hitch, which it should. IF you can keep the rig and all of it's contents UNDER 21,000 lbs., you can tow up to 5,000 lbs. (26k-21k=5k). That will be your maximum towing limit as the limit is now set by the 5k tow hitch.
So, if you need to tow 4,500 pounds, for instance, the rig and all of it's contents should be UNDER 21,500 lbs. Those are the numbers we travel with on our rig as we flat-tow our 4,480 lb. Honda Odyssey. So if your rig weighs 19,500 lbs. empty and you need to keep it under 21,500 lbs., after the water tank is filled you nave about 1,300 lbs. or so of capacity for people, food & stuff. Not bad for two people, but a bit tough if you have a larger crew. Plus, I think the 19,500 estimate is probably worst case. Most likely it weighs in the low 19,000's.
Hopefully this info helps. I did LOTS of research on similar rigs when we were looking to buy ours. I probably would've bought a Tiffin BUT we really needed the dual sofa layout of our Georgie Boy because we had 4 kids ages 1-7, at the time. I apparently forgot a lot of the details! LOL
Good Luck, it sounds like a sweet rig if everything is functional.
~Rick
2005 Georgie Boy Cruise Master 3625 DS on a Workhorse W-22
Rick, Gail, 1 girl (27-Angel since 2008), 1 girl (22), 2 boys (23 & 20).
2001 Honda Odyssey, Demco Aluminator tow bar & tow plate, SMI Silent Partner brake controller.
