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.

47 minutes ago, Mopar1973Man said:

 

You might have done damage to the PCM. Never short these leads together.

 

 

Did you leave the field lead unhooked and the alternator fuse removed during your test drive?

 

 

Good way to burn up the torque converter and transmission. Still you need to find the source of the AC noise. These kinds of band-aids is what kill the ECM, PCM and VP44 because the ultimate source of the AC noise was never found so these computer get damaged. 

I did not short the field wires, only the field terminals on the back of alternator after the field wires were disconnected. This should have no effect on the PCM. Yes I left the wires disconnected and the fuse out.

 

In reality the 47RE transmission is just a B-727 from the 1970's with a OD unit attached to it. I used to have  a 1971 Challenger with a 426 Hemi automatic and it didn't have a lockup convertor and it never overheated. It had about the same size trans oil cooler as the truck has and since I never tow anything there should be no issue with overheating that  I can see with a disabled torque convertor lock up. If I'm missing something please tell me.

While the fuse is out and field leads are unhooked you need to measure the AC noise and try to isolate the device creating the noise. 

23 minutes ago, Citation_SP said:

In reality the 47RE transmission is just a B-727 from the 1970's with a OD unit attached to it. I used to have  a 1971 Challenger with a 426 Hemi automatic and it didn't have a lockup convertor and it never overheated. It had about the same size trans oil cooler as the truck has and since I never tow anything there should be no issue with overheating that  I can see with a disabled torque convertor lock up. If I'm missing something please tell me.

 

 

 

This is true. But these were all gasoline engines. Now diesel is way different where the TQ comes on very low in the RPM span and pump pressure of the transmission are very low. Where gasoline engine never made torque till high RPM's. Lockup was to reduce heat created by the shearing of the ATF in the torque converter since its locked its just a solid shaft so no heat produced.  Just my 1996 Dodge 1500 5.9L V8 with 46RE if I keep it out of lock up it will jump right up to 200*F in no time at all. Once it does hit lock up the trans temp falls like a rock. I've got a few grades I've gotta watch to be sure it locks up in 3rd. This is only 5,500 pound truck not towing either. 

 

https://mopar1973man.com/garage/vehicle/102-1996-dodge-ram-1500/

 

https://mopar1973man.com/garage/modification/232-46re-transmission-rebuilt/

Edited January 30, 20178 yr by Mopar1973Man

My trucks got around 90,000. It doesn't hunt but sometimes won't shift into 4th. Sort of like it's stuck so I have to either let off the pedal or click the cruise control down one notch to get it to go in. So no hunting and no high ac voltage levels. Just loves to stay in third sometimes. I have the Fluke volt meter too.

 

The trans service was due so I had them change out some electronic sensors but it is still the same as before. So I don't know what it is. It works fine except it loves that third gear sometimes.

 

There is a way to lock up the TC electronically on a switch but I think it will ruin the trans if you let it shift in lock up. IBM Mobile has a good set up on his. He tows a fifth wheel too.

 

Mike Nelson, which sensor is most likely to cause the erratic shift? Could it be a bad speed sensor too?

1 hour ago, Mopar1973Man said:

While the fuse is out and field leads are unhooked you need to measure the AC noise and try to isolate the device creating the noise. 

 

This is true. But these were all gasoline engines. Now diesel is way different where the TQ comes on very low in the RPM span and pump pressure of the transmission are very low. Where gasoline engine never made torque till high RPM's. Lockup was to reduce heat created by the shearing of the ATF in the torque converter since its locked its just a solid shaft so no heat produced.  Just my 1996 Dodge 1500 5.9L V8 with 46RE if I keep it out of lock up it will jump right up to 200*F in no time at all. Once it does hit lock up the trans temp falls like a rock. I've got a few grades I've gotta watch to be sure it locks up in 3rd. This is only 5,500 pound truck not towing either. 

 

https://mopar1973man.com/garage/vehicle/102-1996-dodge-ram-1500/

 

https://mopar1973man.com/garage/modification/232-46re-transmission-rebuilt/

In reality is 200 degrees to hot? I am at loss as to what to do. The APPS was replaced several years ago but since I stopped driving the truck I have only about 5,000 miles on it. The batteries are less than 3 years old, I have replaced the alternator with a new Dodge part not rebuilt and the diodes checked ok. With all of this done it still has the problem, what is left to check?

Why does the torque convertor lock up issue only seem to be with the diesel trucks and not with the gas powered vehicles? They both have the same type of system, in other words both have an APPS or TPS, both have alternators, both have PCMs, both have lockup convertors the only difference is the diesel has an ECM and I don't belive the gas vehicles have this. Comments???

23 hours ago, Citation_SP said:

I have replaced the alternator with a new Dodge part not rebuilt and the diodes checked ok. With all of this done it still has the problem, what is left to check?

You said that the diodes checked ok.  What was the AC voltage from the alternator?

 

Yes, you can have new alternator and still be putting out too much AC voltage. Most shops don't test for it either. 

If you are buying or testing at the local big box auto supply, a lot of the clerks really dont know what you are looking for. They just do a basic check and if it is putting out D voltage. If it does you get the big OK. 

 There is a pricey alternator company that some are using here with high praise of the product. I am not knocking their product in the least because some here have them and they seem to work very well. When I look at it on their site there is only one review and it is positive. To quote it, "It spins, doesn't smoke, and produces DC current." Always thought that was odd beings it is the only review they have posted. That is also what I think the common parts houses look for when they test.

I checked the alternator with my Dvom and the AC running vots was .03VAC.

17 minutes ago, Citation_SP said:

I checked the alternator with my Dvom and the AC running vots was .03VAC.

 

That's a passing grade. 

1 hour ago, Mopar1973Man said:

 

That's a passing grade. 

Where do I go from here? It seems that everything I have tested is ok. Any suggestions would be helpful.

Edited February 3, 20178 yr by Citation_SP

I would again try test driving again with the field lead and the alternator fuse disconnected. If the problem continues then the PCM and electrical to the transmission would be my next step to isolate what's going on. I would consider a output speed sensor on the transmission maybe would help with the issue. 

On ‎2‎/‎3‎/‎2017 at 6:05 PM, Mopar1973Man said:

I would again try test driving again with the field lead and the alternator fuse disconnected. If the problem continues then the PCM and electrical to the transmission would be my next step to isolate what's going on. I would consider a output speed sensor on the transmission maybe would help with the issue. 

My friend has a 2001 Dodge 2500 diesel with 50,000 miles on it and he has had the same problem as I have had for about two years. I checked his alternator AC volts and it was .03 same as mine. We will check the wiring at the transmission to see what we find.

I had the same issue a couple years back and went through the usual tricks I could find in the forums. Eventually I landed on the thought that it may be my throttle sensor (those aren't cheap). So I did a recalibration by unhooking the batteries for about 30 minutes, hooking them back up, turning the key on, depressing the throttle slowly all the way to the floor, and letting it back up slowly. Solved the issue, although I've had to do it a couple times. I'm sure I'll have to replace that sensor eventually, but this is good for a pinch situation. 

Everyone has been very helpful in attempting to help me with my torque convertor lockup/unlocking issueissue however I have been trying to correct this issue for the past 8 years and as a result I have driven the truck very little. Just prior to the warranty ending in 2009 the dealer rebuilt the transmission (unnecessary), replaced the torque convertor (unnecessary), replaced 4 APPS sensors (all unnecessary), replaced both batteries (unnecessary), replaced the PCM (unnecessary), and replaced for the second time the torque convertor lock up solenoids (unnecessary). I have rebuilt the alternator using new Bosch rotor, brushes, and bearings. The alternator has .03 A/C volts at the battery while running. All wiring and connections are tight and there is no corrosion at any ground point. I even replaced the stop light switch since one of it's functions is to unlock the convertor when depressed. This truck has no options so things like cruise control, air conditioning, or any other power equipment could not be the source of electrical noise. I replaced the lift pump since it is an electric motor near the ECM. All during all this replacement of parts there was never an error code recorded. I have finally concluded I have an unsolvable issue and  to continue to investigate this problem is futile and it's time to dispose of the truck.

Edited February 13, 20178 yr by Citation_SP

Mike, just need some verification here.  99 Cummins with a power puck as my only electrical mod.  vac reading of .035 at idle. When raised to 2000 rpm I see a reading of .055 vac.  Measured with a borrowed fluke 17?? meter from work electrician.  Is this within spec?  I had the unlock/lock issue about 8 months ago, rebuilt alternator (Bosch reman) and get a random unlock/lock about once every couple of months.  When it happens, it only does it once or twice, fairly spaced out in my hour long drive to/from work.  I usually just clean my posts and terminals and issue won't return for a couple of months.  I am currently in the process of building and replacing all of my terminals and battery wires/grounds as I had the driverside negative pop off the other day which made the issue come back.  I do have slight corrosion of the positive cables.  Thanks!

5 hours ago, Mr. Bojangles said:

99 Cummins with a power puck as my only electrical mod.  vac reading of .035 at idle. When raised to 2000 rpm I see a reading of .055 vac.

 

 

 

You might be getting marginal. I would do two other test.  

 

1. Disconnect the field lead go for a test drive if the problem is gone the alternator fail on the AC noise.

2. Remove the Alternator and have it bench tested at a part store make sure they do the AC ripple test. 

 

Now if both failed plus you voltage test then you basically got 3 smoking guns pointing to a failed alternator.

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

1 hour ago, 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

 

Do you plan on using that full amperage and have upgraded cables running from your alternator to your batteries?  If not, then leave the 140 in place, IMO.  I left my 140 in place, and it has been fine, I could put a bigger one as I did upgrade my cables.

On 3/9/2017 at 8:14 AM, Mopar1973Man said:

 

You might be getting marginal. I would do two other test.  

 

1. Disconnect the field lead go for a test drive if the problem is gone the alternator fail on the AC noise.

2. Remove the Alternator and have it bench tested at a part store make sure they do the AC ripple test. 

 

Now if both failed plus you voltage test then you basically got 3 smoking guns pointing to a failed alternator.

By Field lead you mean the plug or the large wire used for the test?

 

Im reading .025 on the Fluke and the multimeter at the house and it's still doing the unlock/lock again.  Charging used to be 14.5v but now it's only putting out 13.77v.  

 

 

Edited April 29, 20178 yr by Mr. Bojangles
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