Electronic 4x4 issues

[Collin juoni]

Just replaced transfer case shift motor sunday as well as front axle disconnect. All was good after install inspected visible wires and traced back wires in loom to look for chafes or corrosion and it all looked good. My problem came up yesterday when i was heading home from work and started the truck. The 4wd light flashed once then went away so i thought that was odd and went ahead put it in drive and went down the road about a km then the t-case must’ve slipped into neutral or better gears or something so i flipped the 4x4 switch to auto then back to 2wd and all was good. Happened once again today this time a little bit more of a bad situation about the 4th time starting truck to do some errands and same thing 4wd light flashed once then went away i went down the road a little and it felt jerky then as i came to a stop there felt like alot of pressure pushing me forward into the intersection then as i begin to ease onto the throttle i hear a grinding so i immediately put it into neutral flipped 4x4 switch then back to 2wd and it was all good. I tested it when i got back to my neighbourhood and all 4wd modes function and lock in. I have a feeling it has to do with the tipm.. keep in mind ive been having 4x4 problems since i bought the truck 2 years ago and have replaced the shift motor and front axle disconnect twice now any help would be greatly appreciated. Thank you

 

[sleepy hollow]

Have you been able to figure out what your problem is?

I have a 2007 1500 Laramie 4WD with 5.7L. 150K miles. I have not had 4WD since 2022 and finally had time to begin troubleshooting it again this past weekend. I have replaced both the front actuator and the TC Motor over the years which never really fixed the problems entirely. 4WD worked sometimes and not others. I also sometimes got funny noises and behaviors from the TC motor and drivetrain. I also saved the original parts so now I have two TC motors and two front actuators to maybe aid my troubleshooting.

I have a service manual for the 2008 Ram and also can read some of the proprietary trouble codes from the various system components. So far the only code I have read is a C140D which indicates an open circuit to the motor. The circuit from the TIPM to the connector at the motor passes the service manual troubleshooting tests so there is no break in either A or B circuit.

But one of the solutions given in the truobleshooting procedure for all of the various C codes related to the transfer case is to replace the TIPM which is why I am telling you my story and wondering how you are making out with your truck.

This past year I had three separate weird episodes at with my truck. Twice during summer, at a fill up on a 3 hour ride, and at alother local fillup while running errands, when I got back into the truck to start, the truck would not start. The starter turned strongly and everything seemed to be ready to go but it never started. It was s though there was no fuel or spark. No trouble codes were set and after running the battery down a bit (first time only) I simply let it sit for a few minutes. Eventually it started as though nothing had happened. Second time I knew to wait a few minutes. I also had a weird loss of power on a day long drive home from another state earlier in the year. Just lost power while driving. I pulled over, shut her down, waited a few minutes, and then it started and ran as though nothing were wrong. It was quite worrisome at the time as I was quite a ways from home and driving through on a state road through some hilly country in Maryland. Kept making plans for when she shut down again for good for the rest of the day. But no problems materialized.

So, now I am wondering whether my TIPM might be flaking out. If so, replacing it could prevent future weirdness like I just described and also potentially fix the 4WD.

Happy to exchange further info with you or others if anyone has ideas, experiences, advice or suggestions.

 

[Travis77]

I recently purchased a truck that someone had given up on due to a similar problem. They replaced the TIPM with a rebuilt one, which initially improved the issue, but it eventually returned, and I ended up with the truck. The first thing I noticed was that the scanner indicated a CAN bus problem. After removing the TIPM and inspecting the pins, I found two that were corroded, and one was completely missing. I managed to find another harness, harvested some pins and short pigtails of wire, spliced those in, and have been trouble-free since.

So, my suggestion before replacing the TIPM would be to remove it and closely inspect the pins for corrosion. I found all the pinouts on the rambodybuilders site, which seems to have changed. I am not sure if it's accessible anymore; perhaps someone else can help point you towards pinouts. I would go so far as to load test each pin from the TIPM to the transfer case just to determine if there are any breaks or shorts.

On my TIPM, it was mostly CAN bus-related pins that had corroded.

Good luck!

 

[sleepy hollow]

Thank you for the excellent suggestion. I have opened the TIPM box when tracing wires to the TC motor connector. But I did not spend a lot of time beyond understanding the various connectors on the back of the unit so I could identify the one that connects to the TC. When you mention the CAN bus connectors, where are those found? I guess I can go back to the truck or start studying the wiring diagrams in the service manual, and probably find them, but if you could help orient me I'd be much obliged. I have not seen any good diagrams of the TIMP that just shows its physical layout or something like a parts explosion.

 

[Collin juoni]

Hey there! I didn’t realize anyone had actually replied! I am still having the 4x4 issues just for a recap i have the 5.7 hemi sport with the 4x4 auto which is the 246D transfer case. Ive chased wires to some extent ive tore apart my tipm cleaned all contacts on the tipm and all connectors that plug into the tipm and still no 4x4. I have not done any electrical testing to try to track down a short or any sort of load testing because i could not for the life of me find a service manual for free download so i am still searching for that i may break down and buy it. I read various threads saying that people have replaced their tipm and that didn’t fix it, one guy had it at a shop and the shop was really invested in fixing it for the customer so they finally found on this guy’s specific truck that it was just loose pin to socket connected at the tipm understandably these things can spread over time and give false connection so that’s another thing to look into. Theres so many variables with these trucks its not easy in my opinion there is too much electronic reliance every darn thing is ran off the tipm and they are known to fail or be faulty as well as the transfer case control module. Good luck to you and i will try to keep posting in this forum if i find anything or make any progress

 

[sleepy hollow]

I have service manuals for 06-08. Interestingly, the only one that includes the NV246 transfer case is the 2008 manual. I have a 2007 Laramie with 5.7L and NV246 TC.

PM me and I'll be glad to send you what I have.

 

[dodgekenworth]

If it shifts between gears on it own as far as goes into 4wd I would think tipm but it's a guess you can get them rebuilt