2003 M1083A1 Does C7 replace 3126?

[GeneralDisorder]

Thank you for the reply.
So according to the numbers I have a 3126B which apparently I will need a tune on the computer but since you said, if it even drives which I doubt, you know of course what I need to do and that is to see if it moves. And if it does it will mean does it move enough to shift. LOL
I'll get back and I am going to see what the documentation says as if it is labeled as a C7.

Since I am trying this out, I do have a used C7 Acert ECM. Any predictipns as to what happens if I try this one out?
General sir, we will speak later.

C7 ECM will not run a 3126 (correctly, if at all) either. It would not be better than the 3126 ECM you are using. I wouldn't try that.

 

[Lugnuts]

C7 ECM will not run a 3126 (correctly, if at all) either. It would not be better than the 3126 ECM you are using. I wouldn't try that.

When I get these trucks and their problems, sometimes it is just best after diagnostics to see if they start and confirm that the ECM is the problem. I am just saying that if you can start the truck that is 3/4 the battle. I like to know my possibilities to make that happen. Running well is another. After you install an engine, it is nice to hear it runs, holds water, and has oil pressure. The rest is a downhill slide.

 

[Lugnuts]

Here is the conclusion of that project.
Truck is running and back in service/ ECM after several starts adjusted to engine and vice versa.
I don't know how long the engine was in the box.
I flushed the coolant side of the engine and found a very interesting fact; the coolant runs about 15* cooler with the thermostats in as opposed to be out. Also had a coolant sensor and gauge to replace. Also on a note, India as a country is making replacement gauges and senders for the military trucks (12 vdc) Sold in a 3 set of oil pressure, Fuel tank, and coolant. Seventy five dollars for the set and the rascals seem well made and accurate.
All in all, satisfying job and still shows I have so much more to learn!
Thanks, guys, for the assistance.

 

[Ronmar]

found a very interesting fact; the coolant runs about 15* cooler with the thermostats in as opposed to be out.

Heat transfer is about temp difference, surface area and TIME. There are of course a few other factors that interact with and effect these big 3(transfer material, turbulence flow rate ect) . If the coolant is flowing unrestricted, it flows faster and has less time in contact with the heat exchanger surfaces...

SO got a bad thermostat, fine, don't remove it if you don't have a replacement, wedge it open and re-install it so it still regulates/directs flow

This being a bypass type cooling system, without a thermostat to divert the coolant from recirculation mode to send it to the radiator to dissipate heat, you had a lot of coolant simply taking that unnecessary and unblocked left turn at cleveland and passing back thru the engine when the engine was already warm...