So where can i get a sending unit at if thats what tells you what the oil pressure is and is it possible to clean or repair it or just replace it
and could anything be mixed with the oil to help clear the lines out if there is some sludge or buildup

 

You can get an oil pressure sending unit at any autoparts store. Just walk in and ask for it for your year truck.

As for mixing something in the oil... like Crazy said a few posts above, you can try seafoam, but there are a lot of cleaners out there, most of them kersosene based. I've even heard of people using straight kerosene before, but don't run it in there long because it can start to eat up gaskets. What you'll want to do is dump it in the crankcase where the oil goes, let the engine idle for 15-20 minutes, and change the oil and filter. Then, run the engine at idle for another 15-20 minutes and do one more oil and filter change to make sure you got all the cleaner out.

 

Agree with above might want to scale back the idle time with the flush fluid to 5 to 10 min??? I would let it idle then turn off for 20min or so then idle again then dump it. Put in some cheap oil for the first time drive it for 1/2 hour or so and then change again as stated above. I would use 40 weight for this summer and add a bottle of Lucas.