EUREKA!!!!! Got the new Gates belt in today, installed and tested this afternoon. Man, what a difference. No more grinding going into gear, smooth shifting from forward to reverse, diff lock works better, although I did let it roll a bit. Still stutters a bit when pulling off even after turning the idle up a bit. So, now it's get the limiter cap off the pilot screw and see if I can tweak the carb a bit to clear that up.
Travis, I want to thank you for all your input, without it, I would have been lost. There's not a lot of info about the 550 on the internet, although there are great machines, for what they are designed for.
I'll post the results about the carb as soon as I get a chance. May be a while, got a lot going on...
Take care and God bless,
Roger