spliter acting weird

I have a 98 century class with a meritor that's the brand on the stick the splitter started acting weird. at first it would give me a hard time trying to go back on low speeds the problem has gotten worse. I was coming down to Florida half loaded and going through scales a couple times I had to stop and then, to put the truck on gear again, I would have to start up on high gears. It would make that characteristic noise of when you try to force high gears into lows or viceversa once it reaches full speed the problem seems to be gone but it would come back anytime without following any particular patterns
Now I'm empty and when I stop at a traffic light or something I can hear the splitter is getting engaged and disengaged by itself.
While I'm waiting for my trailer to get fixed I'll be going to the Mechanic today but I'd like to have an idea of what are the most common diagnoses to spliter problems and prices of parts
Thanks for reading and for your opinions