HPX 4x4 Transmission Slipping

I have an HPX 4x4 that I have had about 3 years. It has 165 hours. And the transmission seems to be slipping.

When I first give it gas, it feels like it slips a bit before moving. And under a load (with firewood pulling up a slight incline) it feels like it's having trouble pulling.

Any advise on how to trouble shoot/resolve this? I had rather not spend a ton of money with the dealer this close to Christmas!

Thanks for any advise out there.

David - Canton, GA