Just bought this truck about a month ago, recieved with trans and T case in the bed, this past week I got the rebuilt trans back under the truck where it belongs, and heard the motor (318) run for the 1st time since I trailered it home.
Engine is very quiet and smooth when it is running, absolutely no ticks/rattles/knocks.
as title says, oil pressure gauge is dead. (so is gas gauge, but I don't think that is related) Temp and volt gauge work as does tach, and rest of lights/gauges.
Unless gas gauge not working is somehow tied to the dead OP gauge, I am not gonna worry about that right at this moment, just the OP gauge. gas gauge another issue for another day.
This is my 5th square body Dakota and I have become quite used to using my trip meter as my gas gauge, ha ha, but this is 1st one with dead OP gauge.

Upon bolting up the trans, I noticed the old sending unit had been a leaker. Thru the top of the unit and into the pigtail, soaked.

I drained the oil and put new 10w40 into it and a new filter (filter had to be off to get that last bolt into the tranny, anyways, on that side)

After discovering the dead oil gauge, I plugged a manual OP gauge directly into the sending unit port and if anything, the oil pressure is high. I did not let the motor fully warm up, but stone cold, at idle I have nearly 90PSI/ and fast idle, I had around 115 PSI. I have used this gauge many times before and have checked it against other ones so I don't have any reason at this time to doubt its accuracy. I am wondering if my pressure relief may be sticking shut (but that's an issue for another day and another topic heading) truck has been in the garage for a couple of weeks now, temp in garage when I did OP test was about 55*F within garage.

AT THE MOMENT, I am only concerned about the dead OP gauge.
there are 2 pins on the gauge and the pigtail. Can I test these with a multi meter, and what results should I have on both the sending unit itself, and the pigtail/ and under what conditions?