It's partly a matter of being in the right place at the right time <grin> and/or having some understanding of the different NVH objectives in different industries.
For example, I moved from automotive (Ford) to heavy (Class 8) trucks (company name withheld to protect the innocent).
The difference in the truck industry is that, while I was hired by people that "knew" they wanted "NVH" improvement, they really had no idea of what that entails, nor even what they expected me to do, so I've been inventing my job for the past 6 years.
In the farm equipment industry, the desire is simply to get equipment to meet government regulations for operator noise, with no regard for sound quality.
There are, however, plenty of jobs out there for NVH engineers with a solid educational and experience background.
You might even look at companies that supply noise and vibration attenuation devices to the automotive, truck, or farm implement industries.
Best of luck,
- R