I had the same question about gears. Do you mean that the transmission is slipping at low speeds? If the transmission is slipping, then its dying. As AIC above says, a Nissan (or independent) shop might do more for you than an FCA dealer. The deal FCA has with Jatco is that they don't fix CVTs, they just replace them. Fortunately I had the lifetime warranty and FCA replaced both trannies at no charge to me.
About changing the fluid, you're right: the fluid is way past time to change. The owners manual is OTL; CVT fluid should be changed around 50-60,000 miles. I hope its not too late.
I've had two CVTs, the first began humming at 110,000 miles. The replacement got me to 273,000 miles.
Aside from the transmission, my Patriot was remarkably trouble-free. Even if I had to pay for the first transmission, it would have been worth it. Approaching 300,000 miles I wouldn't have put out my own money for a new transmission, but since it was their dime, what the heck?