C15 Acert BXS shuts off-throws no codes HELP!!!!

Thanks Mr. Haney for your input. Based on your response, I described the problem correctly. I will check the speedometer problem, and I'll bet that is it. As for the shut off issue, I'm sure thinking it's the ECM. When the truck dies, all of the lights on the dash light up until you turn the key off. You can reach down while still rolling and start it right back up. We have checked and rechecked every connection that we can think of. We have wiggled every connection at or near the ECM and batteries with the truck idleing and it will not die. I had a 8.1 L Deere in a Terragator that would not set a code after loosing all throttle control. Deere replaced all kinds of parts and never fixed it. I ordered a used ECM and it fixed the problem. Can you sell me a programmed ECM?

 

One more thing, it acts like you have just turned the key off when it dies. There is no sputtering at all, it simply shuts off.

 

Just found out, we have replaced the speed sensor in the back of the transmission, the socket was clean, and the yoke was tight.

 

Is there any way that the speedometer problem could be ECM related?

 

Yes, I mean all the warning lights, like when you first turn the truck on.

 

Here is a critical bit of information that the driver just gave me. When the speedometer is fluctuating, the motor is surging up and down like it's trying to follow the speedometer. In other words, the speedometer fluctuation is causing the motor to surge.