12.7 detroit MAJOR PROBLEM -NEED ASSISTANCE TROUBLESHOOTING

I started my truck up this morning, cant believe what I heard.i started the truck and it wouldnt crank, then my battery started going down.i sprayed some premium starter fluid thru the intake and truck started after chugging for a minute.when it did finally start it idled upreal real high, and a heavy shake and killed

.i started it up again with just a lil squirt of fluid and tried to keep it running with the pedal, but truck just ran the diesel off im assuming what was in the line and then shutoff.Im trying to trouble Shoot before I call the mechanic out because we all know as a op, when you pick that phone up and call its $$$MONEY$$$.then I heard what sounds like metal on metal.

REAL BAD/I CRINGED WHEN I HEARD IT..BUT NO SMOKE OUT DA EXHAUST, HAVE FUEL IN TRUCK.NO WATER IN OIL.So I started it up again this time with another small squirt and the loud what i believe to be metal on metal noise went away.

Then my starter went out so I tapped it a few times and it started up but then it killed again and when I went to start it again my batterys were dead.im not driving it at this moment its been parked for a few months I go over to run it every week to keep batterys charged.

I wanna also note the hard vibration went away, last time I started it up was about a week ago

I should also add I been having this truck for over a year and this is the 1st real problem I had with it

My 1st thought is the injectors or a bad injector, or fuel pump but to my knowledge injectors wouldnt make this sound.I have video of the noise but cant post it, not sure on how to post videos.Best case scenario it sounds like injectors worse case scenario its somethimg inside motor.
When I brought truck it had top work redone but not bottom.

To the veterans ops and mechanics give me your best input,or GUEST ON WHAT U THINK BEFORE I CALL DE MECHANIC
THANKS FOR YOUR INPUT

IF U HAVE N E MORE QUESTIONS FEEL FREE TO ASK TO HELP TEOUBLESHOOT

 

Yes sir..lol my buddy who drives a mac we park our truck at the same yard and he was there when I was trying to crank it, he also told me to be careful also with that starter fluid but I was very minimal with it.i have never ever had to use it.i used to work for a companythat had MACS...they bet there life on them one truck wouldnt start everymorning they sprayed it..the #### truck ate it everymorning for breakfast for months it got to the point where that was da only way to start it, till finally the owner decided to bite da bullet and got the mechanic to pull em, they had grime and black dust build up all over the injectors so I kno about how to b careful with starter fluid.but that makes sense so what ill do is pull my batterys off and slow trickel em over the weekend I just got them batterys about 2 months ago, but I believe the one I didnt change maybe the culprit so i will get a new one as well and have 4 hot batterys,now about that loud rattling noise any suggestions?
No codes havnt checked it, but I will go buy me a odoreader for the truck any suggestions on where and what is a good brand ?

 

Up until now it has ran fine no problems whatsoever....I been having it a while now....the guy I bought it from told me it had a rack job done on it before I got it...but that's pure speculation LOL...no paperwork to prove it ...so I'll check DA battery's n charge em up...then I'll go from there shouldn't b nothing to serious...the rack job was suppose to b done around 700-800 supposedly