If it has Power Steering, then it is driven by a drive belt. Look at the belts and what they are connected to. One of them is driving the P/S Pump.
2 stroke
No.
In the power steering resivoir. If you cannot see it from the top of the engine rear on the passenger side take off the right front wheel and you can see it.
The power steering is a separate system to the engine. The power steering system consists of a pump, bolted to the engine. A steering box, bolted to the vehicals frame and two hoses carrying fluid back and forth between the two. There is no power steering hose "in" the engine.
The Vin number on a Polaris Xplorer 400 is located on the Manufacturer`s sticker that is located on the front plastic just below the oil filler cap. If the sticker is missing you can find the numbers on the frame on the right side of the quad just in front of the engine.
You will screw your steering system. You need to flush steering system ASAP. And of course do not drive with engine oil in steering.
In the power steering box. It is on the left side of the engine under the engine cover. It has a steering wheel on it.
It is the engine that is vibrating and it is just being felt in the steering wheel. Can be a vacuum leak, or miss in the engine.
The hydraulic seals in your power steering will be eaten away by engine oil. Your power steering will start to leek and eventually, it will not work at all.
The power steering pump is in the engine compartment,to the right side,towards the rear of the engine
The power steering pump is located(looking at engine from front of car) on the bottom of the engine on the left side.
If it is a 2 stroke then use any brand of 2 stroke oil mixed to the correct ratio with gasoline.