Im about ready to replace my 550 - 2wheel drive with a 4 wheel drive. I dont know
much about the new mules model numbers but I would like on that is physically the
same size. Dont want to widen my trails anymore! the 550s - 300cc engine seemed to have enough power and speed.
One other question is, what models have hi/lo trans. The old 550 mule only has
single which is kind of low but thats what i like anyway. Did they add a hi range to
the normal range in the new mules or is it really a lower range + normal range?

 

I own a Mule 500 and a 550 and they have been very reliable and tough machines. However, due to their lack of power and 4WD I have "loaned" them out to family members to use and replaced them with a Yamaha Rhino. It may not however suit your needs or desires and I can certainly see why you would want something with which you are familiar. It looks like the Mule 610 4WD is as close as you are going to get to the size of the 550 and still have 4WD with dual range transmission.

My 1990 500 has NEVER had a mechanical problem other than a blown fuse and is still running strong, very reliable machines.