You probably have EZ-lube would be my guess. If you go to the Montana Owners Forum (MOC) you will get the info you need.
I am doing my own bearings. Just have to get the wheels off the ground, keep spinning the wheel, and slowly pump a lot of new grease in.
Be sure to test your brake controller setting on a gravel road prior to thinking you need to spend some money there. When I first got my new unit I had mine set on 9.5 because I just didn't feel like I was getting enough braking out of the trailer. First CG with gravel roads I played around with it and could easily lock them up. Now I have it set on 8 with plenty of brake.