Service.....
You should do a full service on your Doo at least once every riding season. For those who have riding season all year, then you need to pick a month out that you can dedicate to doing your service.
The shop manual does specify a specific service at the 50 hour mark. The oil shows that it's changed at the first ten hours then after that, every storage season or 100 hours, whichever comes first.
You should go over all your seals, motor mounts, coolant, oil, .............There were 4 GTX's made that year, so I don't know if you've got one of the supercharged or not......
You don't necessarily have to take it to a shop but if you've never changed the oil, or done a hydrometer test of the coolant, then maybe you should at least do those......then, you can work into the other things like checking motor mounts etcl....