I have a 2005 and I think there is a lever on the floor board you push to lock in both front wheels. I will have to look at mine. I know there is a knob around the park brake you pull to lock in both rear wheels to pull cause I used it many times when I had the stock knobblies on it. I had to use 4wd lots of times with the stock tires out in the pasture. Just replaced them with some more aggressive tires and ain't had to use 4wd on it yet out in pastures. How many hrs on yours? I imagine you have replaced the fluids and filters. Wife bought her a Mule Trans model about two yrs ago and I use it sometimes. We use to have a Mule 550 2wd back in 98 never had any problems with it other than just getting stuck. I on the list to get a Mule MX model probably be in around Feb or March 2022. I gonna change all the oils filters on the RTV 900 clean it up and put it up for sell shortly.. About 1800 hrs on it. Other than a battery just normal maintenace.
