00 Rancher ES stuck in 2nd gear
That it doesn't shift manually would indicate you don't have any problem with the electronic shifting part of your wheeler. Sounds like a tran linkeage problem. I think there's a product improvement campaign on your machine having to do with the linkeage, the shift plate specifically. I believe it's a current bulletin yet, and Honda (I think) will cover that specific problem yet even though your wheeler is out of warranty. If it is a different problem, you'll probably have to pay out of your pocket.