Got a 2000 Dodge Durango, 5.9 Magnum V8, 46RE, 222K Miles, A lot of new parts in her.
All new front-end parts.
Blew the water pump while driving her so she got a new water pump and belt.
Then the fuel pump went out, so that got replaced. Not cycled correctly though so she got cranked on until she started up and ran. (As I didn't replace this part, didn't know it didn't get cycled correctly and drove it) Ran fine for 40 minutes of my hour and 15 minute drive home. Threw her battery voltage gauge all the way up past 18. Limped her back home, had to keep pulling over and putting her in park to let the access power built up pull off the battery. Took about 3 hours to get back to where I was going. Started taking more and more time to pull it off, but eventually got her home. Swapped the alternator and battery for new ones ($320) out the door as unfortunately I cracked the battery and the voltage regulator in the alternator was done so we swapped the alternator for 136 amp. Ran completely normal and fine for a month until today, passed someone and gave her a little gas and threw the voltage all the way back up to 18 so I pulled off and let it come off again, started down the road as I was only three miles from home and she threw it again and faster than she had done before. With the battery voltage sitting at 18 I shut her off after 5 minutes of it not working to pull the access back off. Let her sit for 4 minutes and tried to start her and the battery was reading dead. Got her to start and come to life by putting my foot on the gas until she was where she was supposed to be about 15 on the gauge. Ran fine the rest of the way home.
Ground wire for battery a bit corroded and keeps happening but I don't believe this is the problem. Maybe I'm wrong on this one?
I'm at my wits end with this truck after owning her for 10 years and doing all the repairs myself. Any help is majorly appreciated; or any ideas of something I'm missing.

 

The voltage regulator is actually part of the PCM, not the alternator. Sounds like yours is dieing. Couple options, replace the PCM, or, change it over to an external regulator. Trouble is, with the external, I suspect, given your symptoms, that you won't be able to leave the stock connections in place, so, the PCM will whine about alternator output.... or some such. (which will trigger the check engine lite.) Your local parts store should be able to get you a rebuilt PCM, flashed to your vin..... 2-300 bucks most likely.

 

I knew it was part of the PCM, but thought there was one in the alternator anyway. That's on me for sure. Looks like the PCM is about $400 out the door for my local parts store. I do have a 99 parts Durango same everything. Think I can just flip it over to my daily? Doesn't sound like its grounding out or anything right? Just don't know why it would have waited a month to do it again.

 

It may be a short in the wiring somewhere..... and those are always oh-so-much-fun to find.......

I don't think the 99 will work, as a sensor in two in the trans changed for 2000...... Figgers huh?

 

Are you sure the sensors changed? I did yank a 1999 Dodge Ram trans and drop it in her for a while until about a year later overdrive went out in it and I was back to the hunt on a trans. They are running that stupid rare 46RE trans in it.
Figured my best bet currently is to fix those battery terminals and just replace them. Then the 140 amp alternator fuse. I did read somewhere that it's got a "fuse link" between the battery and alternator just don't know exactly where that is or what it is.

 

On the trucks they did. The pressure sensor was one change, and it had an entirely different resistance vs. temp curve. Symptoms of a sensor mismatch was trans temp light coming on, and overdrive being disabled, fairly shortly after startup. But, that was for a newer sensor in an older truck. Going the other way..... not sure how it would react. Another change was the trans range sensor. Went from 3 wire, to 5 wire, and the 5 wire has a different mounting hole. (larger, I do believe.) So, havin' a look at what you have in there for that one, would be good.

 

Interesting, she ended up getting a different trans now but worked just fine for a year.

Gonna try a few things before the PCM tho, just cause she's overcharging and not undercharging so before the pricey fix I'll try the cheap fixes first.

 

That seems perfectly reasonable.

 

Updating this, as it turns out… boyfriend install a fuel pump with his grandpa. They didn’t listen and just started her right up without cycling. Sent a surcharge through her, blew the alternators regulator and bam boom bing.

New alternator, battery, and she’s good as new. Still running strong.