Been wanting to go to a 200amp alternator, going to be installing a 12,000lb electric winch. So installing a new alternator and a noise isolater would probabely be the better answer. Is all that the noise isolator is a capicator????

 

When you talk about erratic trans shifts, exactly what is it doing? I may be having a similar problem and hadn't considered a voltage problem yet. Had the trans "flashed" in hopes it would fix it but it didn't.

 

Mine would come and go. Like we told you, get the transmission noise filter and you will fix it. I dont think you need to replace the regulator.

 

try measuring the AC voltage at the alternator..it should be low..I would guess less than 0.25V.. any more might cause problems. it would also indicate a bad diode.

Alternators are 3 phase generators. the diodes convert this 3 phase into DC.

-dkenny

 

Tranny was going in and out of lockup in 3rd and 4th. Problem is caused by a multitude of problems:

Bad grounds off of battery to body, frame, engine and ECU to body.
ECU voltage regulator for alternator.
Diodes in alternator.
worn alternator brushes skipping on commutator in alternator.
bad wiring connections on back of alternator.

Cleaning the grounding points to include sanding the paint off of the body, frame and engine were grounds connect helps alot. Also the grounding bolts/screws get corroded and need replaced.

If its alternator related, the big wire coming off the altnator going to the ECU runs through the wire loom with all the wires that are coming or going to sensors and back to the ECU causing the sensor wires to pick up stray voltage spikes including the wires coming off of the APPS and will cause tranny to go in and out of lockup.

ATS has a page were it shows rewiring the APPS wire back to the ECU, allowing the wire to get out and away from the alternator wire in the wire loom that may be causing voltage spikes.
ATS and other compainies like BD diesel sell a noise/sponge isolator that I believe is nothing more than a Capicator that can hook into the big wire off of the alternator or the APPS wire going into ECU. This isolator basically will absorb any high voltage spikes and keep the ECU and tranny happy. Not a bad idea but if the alternator is the problem and its caused by worn alternator parts why not fix it. If the alternator regulator in the ECU is bad then the alternator would be charging at very high voltage not sure how high but I believe higher than 16 volts.
If a diode was out than it can also cause the alternator to charge high but also if the truck sits for awhile it will drain the battery. Trying that now, going to let the truck sit for a couple of days and then check battery voltage.
If the brushes are worn it will cause them to skip on the commutator and cause voltage spikes and the brushes need replaced.
For me; if any part of the alternator is bad I'm just going to replace it with high amp alternator because of the big winch I'm going to install, besides I believe the alternator is the original and I have 142K on the engine.
I also noticed while cleaning all the grounds that Dodge used small ground wires going to the body so I'm adding bigger grounds from the engine to frame and to the body.

 

That's exactly what my trans is doing! I brought it to a trans shop and they connected it to a diagnostic computer and it showed the converter switch going on and off. I then had the computer "flashed" which is like a reformat. Hoped that would help but didn't. I'm going to check my grounds but last fall I also experienced some alternator problems where it would randomly not charge the battery. If I noticed the voltage down I could shut the truck off and restart it which would bring the voltage back up. Think I will have my alt checked and rerouting the cable sounds like a good idea. The noise isolator also sounds like a good idea.

 

Poblem with most noise isolators or capicators is they smothe the voltage and do NOT ALLOW FULL THROTTLE DOWNSHFIT. A band aid covering the real problems outlined obove. Also, there is no one cure fixes all. Batteries, alternaor and wiring and electrical connections are the BIGGIES for this unlocking condition. Also be sure and check the two gray connectors near the pass side battery negative battery. some actually cut terminal and solder wires solid....

 

Good info, test drove a 99 today that was doing an odd shifting in and out at freeway speeds...