HELP!!! I'm stock in Ft. Stockton, TX

I'm an owner/operator of 2010 International Prostar with Cummins ISX
As I was driving my truck, I noticed that it started shaking like I'm driving on bad road. I puled over and realized that my engine is shaking, like it wants to jump out of my truck. The exhaust is blowing white smoke like a steam train. I found a "Mom & Pop" diesel shop in Ft. Stockton but I'm not sure that the mechanic knows what he is doing. First, he said that it was TURBO, now he's telling me that the turbo is fine. Now he's blaming an oil cooler. Computer show only one error code: "Exhaust temperature is too high" and this mechanic doesn't know where to look next.
About 1000 miles ago, I noticed a strange noise (not loud) coming out of my engine, but I thought, I'll make another trip and take it to the shop. Well, it didn't happen. Now I am stranded in the middle of nowhere...
I don't know whether to stay here and let this guy figure out what's wrong with my engine or call the wrecker and have me towed to the nearest International/Cummins dealer? I'm 320 miles from San Antonio and 160 miles from Odessa, TX .

 

677510

 

It's not that I'm cheap. I just spent $5,000.00 on my trailer repair and had no more money left. Yes, it is knocking now, but it wasn't knocking before.

 

A little history about my truck:
1. The coolant likes to play "Hide and go seek" with me. Very often, I see a message: "Low coolant". But as soon as I relieve the pressure of the coolant reservoir, the level of the coolant goes back to normal at MAX.
2. My oil pressure remains at 30 PSI for the first 10,000 miles. Then it goes down to 25 PSI, even 20 PSI very quickly. Thus made me going for the oil change every 10,000 miles. About 30,000 ago, I switched to Mobil One full synthetic oil, hoping that it will increase my oil pressure, but it didn't. This mechanic is telling me that I shouldn't have switched from mineral oil to synthetic on 600,000 miles truck.