Ok Gang...I've got a for sure way to diagnose torque converter lock up issues where it lock and unlocks at about 45-50 MPH. I had a gent call me yesterday with this problem and he's replace both batteries, alternator and the APPS sensor. Attempted all the different wiring issues (adding ground, tinfoil etc.) nothing worked. Like I told him the truck ran 11 years without all this stuff and doesn't require any wiring change to make it work. What it needs is the damaged part to be replaced. So he's returned the wiring back to stock setup.Now I told him to unhook the alternator fuse and take it for a ride... Guess what... No problems! Even though he replaced the alternator it has a damaged diode in it and it bleeding AC noise into the electrical system.So before doing any wiring mods, tinfoil, adding grounds, adding filter... PLEASE! Bench test your alternator! This is the second time I've suggested this and both time resolved the torque converter lock up issue.

After getting the alternator rebuilt last year the problem went away. Now it's back. Serenity now!!!

On 3/14/2017 at 8:41 AM, Mlegens86 said:

I have a 2001 dodge ram 2500 that is pretty well stock. I just ordered the 180 amp alternator from nations. My question is do i need to upgrade the 140 amp fuse since its a higher output alternator? Thanks in advance

I have been running the nations 180amp with the stock wires and fuse for 6 months no issues yet, nor do I expect any.

OK so I unplugged the two wire plug from the alternator and it still locking unlocking.   Now I'm really lost .

Typically I get people to unplug the alternator field lead and remove the alternator fuse. This just make sure the alternator is not producing any power or has any connection to the batteries. 

 

It also could be the output speed sensor too acting up. 

Edited April 29, 20178 yr by Mopar1973Man

Mike,  I didn't remove the fuse.  I didn't have a screw driver with me to do it.  Unplugged the field wire and checked voltage at batts, 12.7.  

 

Now, I put my Napa brand alternator in and took my Bosch to get bench tested, it passed autozones tests.  They don't know if it did a ripple test but the paper says it passed lamp/diode trio, regulator, and rectifier.

 

No cel, no codes present.  Hasn't done it with the Napa alternator but it's putting out .4vac at idle which I don't like.

If the field armature happens to have a bit of magnetism it might still produce AC ripple. This way pulling the alternator fuse you completely isolate the alternator from the circuit. 

I advise to no end the load testing of your ground and battery cables, My passenger was fine, but my drivers side was marginally passing. In the end the cure to my lock up issues was the ground cables. I replaced both to be safe, even thought just the drivers side was bad.

Ok guys I'm having the same tc lock up problems wasn't doing it till I put 35's on the truck. It's not everyday thing. It may go a week and never do it then again it may do it everyday mostly are 40 to 50mph.

Seems you already know the issue then, but just for redundancy, get the volt meter and check and go from there.

On 8/23/2017 at 1:23 AM, notlimah said:

Seems you already know the issue then, but just for redundancy, get the volt meter and check and go from there.

But if it was the alternator would it not be a everday thing

That might not be your problem but it is an easy test to rule it out. 

9 hours ago, Hudsondust said:

But if it was the alternator would it not be a everday thing

 

No. Like right now I'm fighting an alternator AC issue but by the time the alternator cools the AC noise drops back to normal levels. Like yesterday I was hauling the RV home and the under hood temps were rather high. The cruise control was making some weird changes coasting in the wrong times then accelerating at other times when it should be coasting. Once the alternator cooled off as I got to Council, ID and there was cooler air the problem disappeared. So no it's not always a constant everyday problem and this is why I highly suggest you do not use any wiring mods or ground relocations because you are capable of sensing the problem early and given plenty of warning of the issue. 

My truck was only doing it when it was humid out.   Tested the alternator and it came out good, so I cleaned the battery terminals and added dielectric grease to the plugs. 

 

Turns out the passenger battery neg lead was causing the issue.  Cleaned it up greased and now I don't have anymore lockup issues.  

 

testing the alternator is ALWAYS step 1.  

The thing that bugs me is that it seems to be common for these diodes to be failing short (closed). The only thing I know of that causes a diode to short circuit is a transient voltage spike. Maybe these things should have Varistors before the rectifier to suppress the transient voltage spikes. I'm also willing to bet that a lot of the ac ripple noise is the dc filter cap open circuiting as well though.

 

A few months ago I had all 6 diodes on a 480 volt 3 phase bridge rectifier short on a brand new piece of equipment. It was almost unheard of and we never tracked down the problem. It got blamed on factory defects on the diodes.

 

-Kole

Edited August 29, 20177 yr by kzimmer

I just posted it's in my thread on busted gear case. Apparently brake light switches and headlight switches do waky stuff, especially when towing an aluminum trailer  ( what I heard).  Wireing gets hot and melts

I found when checking mine 2001 dodge with shifting issues. I cleaned all the common grounds and cleaned battery terminals as every one has and did the A/C out voltage etc but everything checked good. Then I check but found most problems are on the passenger side battery two grey plugs connectors going to the body grounds take them apart and clean them up really good. Then I checked the alternator ground and found it reading .022 which was bad so I did the same check to the block and got .005 which showed the bracket was not grounding the alternator. This video has a great check out for checking grounds to alternator case and body grounds fixed my problems for over a year now. Don't forget the dielectric grease on the bolts on the alternator bolts to the case. 

 

A lot of people get over zealous when cleaning grounds. They start to grind or sand off all the paint around a ground lug attempting to get bare metal contact of the ground lead to body or block metal. Be aware this bare metal now will rust quickly. The only thing is make sure that the screw is cutting into fresh metal or the stud is clean and rust free. No need in sanding off large patches around the lugs. 

Couldn't I use just an extra amount of dielectric grease on the sanded off paint?

 

My 2001 has trans hunting every once in awhile. I cleaned every ground and it went away. VM shows marginal volts AC on the back of the alternator which gives me a great chance to test and clean more things/ find what will make it stop hunting.

 

The other day hunting went away when I just retightened the battery cables after I disconnected them to do some work. Now it's back again. Even though I tighten them well enough so as to not break the cable clamp, I noticed they were not real tight after the last cleaning from about 2 mos. earlier.

 

Problem is the clamp breaks at the bolt area if too tight so I'm going to try some small screw clamps over the posts.

 

Does anyone know if using what electricians use called NOALOX on the battery posts would help ?

I think its a dielectric grease with a conductive lead or aluminum dust mixed in.

 

 

 

 

 

 

 

 

 

 

 

 

Edited September 3, 20177 yr by JAG1

15 years later and never cleaned a ground lug or ground screw. I've had my fair share of alternator issues, I think I'm on number 5 now for alternator replacement. I've only removed the battery cable maybe 5 times in the entire life of the truck now. Manual trans will show this AC noise issue as a cruise control that surges and dumps randomly. I've not unhooked a single ground lead yet for cleaning. If and when I do I will not sand the paint off the metal I'll just drive the screw back in the hole only if the screw hole is fresh clean metal If not I will relocate that ground lugs slightly. As for the ground studs those clean the threads up with a small wire brush. Main block connections as long as there no rust between the bolt/washer and the block just screw it back down. You have to remember the body of the truck was completely sprayed with paint and then the wiring just simple bolted, screwed or nutted to metal. They did not sand back to bare metal or make exposed metal. Then the truck proceeded to run 7-12 years without an issue. If I suspect a ground issue I would opt for the voltage drop test over sanding paint off the body. 

Maybe a high resistance ground has caused you 4 failed alternators, haha. I kid I kid.