I have a 2001 2500 with 136k miles. My truck just developed an issue where in between 55-60 mph, the truck acts like it is slipping in and out of over drive. Is that the transmisson or is the the tps going in and out of lock mode? I am not sure what rpm that it happends at but it happends at lower speeds and it seems like the same issue.

I checked the tranny level and the fluid color and it does not look bad at all. I have no idea when the last time it was changed but it the fluid is the same as the truck it looks pretty **** good.

Any help is appreciated.

Thanks

 

Clean/check your battery terminals. On the Suncoast Transmissions website they show how to modify the ground between the ECU and the alternator I believe. Might solve your problem.

 

that or my bet is the TPS

 

mine was a ground issue. Put the DTT noise filter on and its been good for 2 years now.

 

2nd on the clean the battery terminals as a 1st step.

 

When this happens, acts like it is slipping out of gear, when you step on the accelerator, does anything happen?
I have the same truck, same year and same problem. I ended up replacing both the lift pump and the injection pump to finally get that to stop. I was told that it was my TPS but it didn't solve my problem.

When I would drive at 55 mph, it seemed to hesitate, slip out of gear, miss, etc.. But when I stepped on the gas, nothing happened. I would just coast until it would finally "catch" and allow me to run. It is usually the lift pump when this happens, but if not fixed right away, your injection pump will be pulling double duty, and you will need to replace both. The VP44 is very expensive, like $2000-$2500.

 

There is no ONE CURE FIXES ALL for this condition. I suggest a systematic diagnois and repair as indicated in first thread on the CumminsForum.com.
Sometimes cleaning terminals seems effective. Frequentlly shielding and add a extra capicator to alternator effects a repair. Sometimes it takes the bucks for kits by aftermarket tranny guys to supply fixes. Installing these kits first does not gurantee repair. JMHO

 

Run a ground wire from PCM to the negative battery terminal fixes this problem everytime.

 

Tried that on mine... NOPE

 

Here's a free fix : Clean all of your ground wires.

The effect that is occuring is known as a "ground loop". Ground loop cause unwanted electrical "noise" on electrical and signal lines. The lockup clutch is controlled electrically and a noisy control line will make it "hunt".

http://en.wikipedia.org/wiki/Ground_loop_(electricity)

Dirty connections, corrosion, and loose connections all contribute to ground loop. Fixing it is easy though. Generally involves cleaning ALL ground connections affecting the transmission and controlling it. Batteries, frame connections and the PCM on the firewall all need to be cleaned.

IMO tin foil shielding and power filters are simply band-aids that mask the underlying problem if left unchecked. And like I said before a simple cleaning with a wire brush and a piece of sandpaper will normally fix the problem with the lockup clutch.

Here is one of my posts from another thread involving the same issue.

I had the lockup issue and it immediatly was solved after cleaning the gounds.

 

man,

thanks so much for the replies. i went ahead and had the tranny flushed and put a new filter and fluid in it. it was time. i will try all of the grounds and bettery connecitons next.

great help. i will keep you posted.

 

#1 clean baterry connections
#2 do the suncoast APPS ground and reset the APPS
#3 do the shield on the alternator charge wire
#4 install the capacitor on the alternator

 

I cleaned battery terminals and problem was gone..... since I also did a fluid/filter service and today I cleaned the ground terminals mentioned above. To me the noise filter and wrap is a bandaid over the "real" issue?????

Mine worked great for as long as I owned it, a year and a half, and 2 weeks ago was havin an issue....... still tryin the cheap/free tricks before I step up to a new trans......

 

mine had small crack on one terminal, replaced no more problem.

 

Correct, if you don't fix what is causing the electrical noise/interference, then a noise filter won't fix it. It MAY help, but it does not fix the problem.

Remember, corrosion is one of the things that contribute to ground loop interference (changes the electrical properties of the metal involved). Corrosion take a few years before it manifests itself into a problem.

My theory is a twofold problem when Dodge built the trucks :

1 - They painted the trucks BEFORE installing the wiring. Paint and clearcoat are poor conductors.

2 - The ground wire they used to connect the PCM to the chassis is not sealed. It was just a copper wire with crimped eye terminals on the ends. I know the auto manufactures want to make the vehicles as cheap as possible, but that is not something you should skimp on IMO.

Even the equipment I work on in the Coast Guard (radar's, radios, and other electronic stuff) is not immune to ground problems. There have been several times when a piece of equipment was not working correctly because of a dirty/broken/disconnected ground wire. Those are some of the more difficult problems to pin down too since is is very easy to overlook a simple ground wire.