on 2003 48re. My truck stranded me yesterday. We think it has something to do with this TQ management. Is it all electrical or is it mechanical also?
We think it is inside tranfer case. Truck will go into all gears and it will pull for just a second or two and then stop. It has park. All shafts are good. In neutral it will rev to 3500 RPMS. In drive and 1-2 it will only go to 2500 RPMS and then start backing the RPMS down and it will jerk back and forth like its trying to go into gear but it wont. The tranny is ok - fluid good. Just ahd it upgraded. I had another thread about defueling and TQ managemnet was brought up several times. We think whatever runs the TQ management has puked. Anyone with info how it works is greatly appreciated.

 

I just read through 5 pages (over an hour) of the threads underneath the search of 'Torque Management'. I understand why it is there - to keep the cummins from tearing up the tranny. But what I dont understand is -'how' it works- completely. I know it is tied into PCM and all because when we installed the BD RAD we cut wires to and from.

BTW for some reason the RAD didnt help me on the bottom end. Talked to Cris at BD and he told me it wasnt made to help on the bottom -just the speed limiter. ??? How come it helps everyone else who has installed it? - I asked. He said I dont think it does help them. He designed the thing and he said it wasnt made to do what everyone on here says it does. ???

I understand the computer senses a load and defuels to keep TQ down-but is there something mechanical in transfer case that helps with the management of the TQ also? Again -we think something mechanical helps the TQ management -someone point us in the right direction.

 

Did you check for codes yet? I would do that then unhook both negative battery cables then turn the key on. Then reset your APPS. You need the batteries unhooked for a minimum of 30 minutes. Look in the FAQ section for the proper procedure. This may help unless something is really broken.

 

Nope. no codes. first thing I checked.

 

Did you try unhooking the RAD yet? I know it's a pain but that's where I would start......

 

Thats the second thing we did. You and I think alot alike. Thanks for your help.

 

The low end TM your talking about is only programmed into the early 2003 trucks with the 47RE transmission. On your truck, it will disable the portion of TM that limits how much boost you can build at a stop (as in building for launch at the drag strip) and your top speed limiter. That's it.

As far as what controls it, it is all electronically controlled by the ECM and PCM based off RPM, VSS (vehicle speed sensor) and the ECM torque load calculations. Nothing fancy and no hard parts in the trans that have anything to do with it. The only clutches you have besides in the torque converter are in the overdrive housing, and as far as I know, those are only engaged when you hit high gear.

It sucks because you have so many electronic gizmos on that rig and they all should come off as part of step #1 to figure it out. Everything that controls or could affect fueling or defueling needs to go, the RAD, Juice & Attitude, etc., ....basically needs to go back to a stock truck and go from there. It almost sounds like you have a bum torque converter to me.

 

I was waiting for you to chime in Brian!!!
I thought about a bad converter too but that wouldn't cause the trans to go in and out of gear though. Unless it was just slipping really badly giving the impression of going in and out of gear. What I find odd is that it threw no codes!!!
Maybe the Vehicle speed sensor has gone bad. The RAD ties in with the ABS system. Maybe the issue lies there. I totally forgot to suggest removing the Juice!!
I would unhook the batteries like I suggested earlier and see if that helps. Sometimes doing this resets sensors that are causing problems.

 

One thing about TQ con. is its rated around 1500 and over lbs of TQ. Supposed to hold over 600 horse. I am nowhere near that. Its only been in there for 4 weeks and I have really never been really that radical with it-yet.
4 runs at the strip and two runs on a sled. And all the time that was going on I still had defuel and TQ Mngmt crap slowing me down.

A question about TQ mangmt- how come when you go low lock its not there?

 

Well, I never read anything definitive, but it's my understanding that TM defueling during shifts, 1 to 2, 2 to 3, went away with the 48RE. That doesn't mean that the 48RE trucks don't have any TM at all.....I just don't know what it is and when it rears it's ugly head. The severe TM that you see on the 47RE trucks was there to protect that tranny. Remember, even the lowly 2003 250hp SO engines put out more power than the HO from 2002, yet the trans wasn't changed. Whatever TM is present, is disabled as soon as the converter is locked. If your at the strip and manually lock the converter in a low gear, any TM programming that your rig has turns off at that point. The top speed limiter is still there though.

I still wonder if your barking up the wrong tree. A bum stator in your converter could feel like defuel, and not be noticeable once the converter locks as the stator is taken out of the equation. Or a converter that is constantly trying to lock (lock...unlock) when it shouldn't could feel like an up-shift, down-shift problem. What are you using to manually lock your converter? Whatever it is could be brokey, sending erroneous lock-up signals.

 

When the truck was new it had the same symtoms. Drove it about 1 year before valve body. Another year before the mods I have now. It has always pooped out off the line since Ive had it - except in low lock 4WD.

The valve body I have now is activated with a toggle switch.

 

We think we figured out the problem on why I was standed. Valve body stuck-pressure dropped and the clutches burnt in the tranny.

 

So did he just not clean up a bore when he did the VB and one of the valves stuck? Glad to hear that he found the problem. Hopefully he's covering the whole repair.......

 

We have wroked on the tucks tranny several times upgrading. This is actually the first VB failure he has had with a loss of pressure. The only thing we could figure was dirt or spec of silicone - something made it stick. He is a stand up guy. Stands behind his work - has ever since I have known him. Youd never meet a nicer guy.

 

Sounds like Timinva up here. He works on everybody's trucks in our area and is a great guy. He lets you help if you want and he will explain everything to you as he does it so you can learn. He also has a 500hp 06 CTD and a 650hp 2nd gen so I think he knows a bit about these trucks.... Anything I didn't do myself to the truck, Tim has done.....

Good luck with yours.........