I have 1998.5 Cummins with 250,000k. My tranny only has about 40k. This problem persist with my truck often. It's the normal tranny lock amd lockup problem notortious with these trucks. I know this is a popular topic. But I can't find any threads on it...pertaining to the alternator.

I've tried about everything.
1. Disconnect battery cables.
2. New Battery cables.
3. Cleaned APPS Sensor
4. Checked and cleaned grounds
5. APPS reset by slowly pressing and releasing brake pedal.

I had my alternator tested this morning. It's only reading about 11.5 to 12 volts. I was told it had bad diodes and should be reading about 13.5 volts. My question is, could the alternator be causing this problem now???? In the past I've been able to disconnect the batterry cables for a while, clean the connections and everything would be fine for a few months. Now I can't get it to stop.

Any suggestions would greatly appreciated.

 

it should be around 13.5 volts, but it could be the altinator, or a failing regulator in the pcm, causing the low voltage, if there are failing diodes putting stray a/c currents through the system, that will cause tc lock-up problems, first try cleaning all the ground wires including the one on the pcm, battery terminals, and grounds from the battery to the body, if that doesnt help, maby go after the altinator, also shielding the altinator wire has cured this problem, as well as adding a ground wire the the apps sensor (black wire with yellow tracer pin#4)

 

Ok, I tried adding the ground wire going from the APPS black w/ yellow tracer back to the battery and that didn't work either. I guess my next step will be the alternator.

All battery cables are clean and tight.

The voltage guage on the guage cluster takes about 30 seconds or so to show the batteries are charging correctly, showing low at first. During that time my "Check Guages Light" remains on until the correct voltage is met.

Any other suggestions before I go buy the alternator???