I have been looking for a long time to upgrade my gears, but I don't know what spline I have. I have a 2008 Ranger Sport 4x4. I know I have 3.73 gears with an open 8.8, I just don't know where to start looking for new stuff. Any ideas? 28 spline or 31 I believe are the two options or I may be way off. I'm lost when it comes to this stuff.