I have an old 8970 that has just started randomly shutting down while it is working. It does not do it when it is cold, only after about 50 minutes of pulling the offsets it turns off completely. It restarts immediately, and runs hard until it shuts down. The check engine light comes on once it shuts off which should give flash codes when the button is pressed on the module under the field cruise dial – the problem is, my module doesn’t have a button – it has another dial … which is puzzling to any jd mech that I have spoken to.We are guessing the ecm is actually fine if it is throwing some code, so we have started unhooking the sensors to reduce it. The engine does not overheat, it runs very well until it reaches operating temperature and then shuts down, restarts fine and then only has a couple of minutes at best before it shuts down again.
I have an 8970 that did the same and ended up being the ECM. Back then it was $ 1600 and Cummins had to come in and plug in his laptop to program the ECM. He ended up with about $ 2000 in total, but it was fixed – correctly. You could go with the mechanical conversion, which is what you would probably do if you had to do it again. Do what you want, but I had a couple different “mechanics” check my 8970, but it took a Cummins mechanic to fix it.