High Oil Pressure

Most likely, if the filter isn't plugged, the pressure relief valve is stuck. You don't say if it is gas or diesel. On the gas, it is on the right side of the block, just above the pan, near the center of the engine. On the diesel, it is on the front of left side behind the injection pump (at bottom). It may be hard to work on it with the side frame in place. Take off the large nut (looks like a drain plug on the gas) and remove the spring and plunger. On the diesel, it is a jam nut and threaded screw. If dirt got stuck between the plunger and the block, it may be tough to remove. Leave all the spacers in the plug and reassemble after cleaning and lubricating.

The oil change and filter may correct and it is the easiest, so do it first.

Soundguy