I just was given a '91 Polaris Big Boss 6x6. Did a little maintenance work and it started on the second pull. My only problem has been putting into gear while started. When off, it is easy to put into all gears, but when started it will NOT go into gear. When I try to put into gear it makes a grinding sound, almost like a clutch isn't pushed all the way down, and if I shove it into gear, the machine shuts down. I called a dealer and spoke with a mechanic and he told me it may be the reverse override switch. He told me to to find a 3 inch black box under the front panel and unplug the black wire and it should fix the problem, No dice. I have had no luck, and are asking for help. Any and all suggestions are welcomed.