'03 duramax/allison, 16k miles pulling 3500lb trailer........

coming to work this moring with my trailer so i can go to the racetrack after work to dial my bike in, trucks running fine, get off expressway stop at light, light turns green hit gas tach jumps to 2500rpm and truck hardly moves, then engine light on dash pops on.. hit it again, revs up hardly moves, then "shift range inhibited" pops on the DIC.... WTF???? limped it to work for the next 2 miles. 1st and reverse are locked out, when you put it in drive it BANGS HARD into gear. its obviously starting out in 2nd gear the way its acting since 1st is locked out.... turned it off let it sit for a while, got reverse back sorta, it does not seem right at all. what gives here, now i need to get my trailer home somehow......

guess i wont be going to the biggest bike drag race of the year this weekend here in NY now with my bike since i now have a truck that cant pull ****. must say i cant beleive a truck rated for what this truck is bangs the tranny pulling a puny 3500lb trailer with no fore warning at all.....

any way i can get this thing to give me 1st and reverse back so i can get my trailer home???? any ideas what could be wrong here?

Are u running any power boxes?

When was the last tranny filter change?

Stop by a dealer and have them rest it.

has edge on it on, i havent been using the power much in the past few months since diesel prices have been so high i have been driving like granny most of the time...

did allison filter at somewhere around 8k??

I'm far from an expert but thats the same thing that happened to me when I warped my C1's.

PM Eric and see if he has any ideas.

well i just got off the phone with my buddy in denver who rebuilds and fixs these trannys weekly. he feels that its 95% chance that its electrical problems of some sort, not really a tranny problem, some chance of a bad shift solenoid. i guess if theres some voltage/resistance problems going to the tcm it can jack the line pressure, and can lock out gears (which its doing). if i could only get the codes outta this thing he says it would be easy to tell if its electrical or a actual tranny problem, says it could be as as simple as a bad ignition switch....

have to try to limp it and my trailer home at lunch then i guess it will have a date with the dealer this weekend..... bummer.....

It might be NSBU switch but I don't remember anyone having the banging problem when shifting into gear. Just a thought. Could it also be C5's?

Sure it's not just limp mode?

Sure it's not just limp mode?
I'd say it is limp mode.

PM me if u want Eric's phone #.

what does it do to tell you its in limp? besides not driving right!

the DIC read out "shift range inhibited" on both 1st and reverse.

not sure why it would go into limp mode, i got off the xpressway after the truck ran fine the whole way, stopped at the light and when it went green the truck no go...

After you cycle the truck on and off the limp mode should reset (codes will still be there) and you should have all gears back again until you over power the tranny again (it gets easier to limp it the more times you limp it). This sounds more serious to me.

When I limped mine (stock) I was on the downshift from 5th to 4th and the TC lock let go (clunk) and my rpms went to redline. I then couldn't get out of 4th gear until I cycled power on the truck. Then everything was back to normal.

When my NSBU went it would bang into gear pretty hard... that would be my first guess I have seen threads on here that that is covered under 100k mile emissions.. you can do a quick search on here... The electronics can be tricky, most of the time when a valve or solenoid sticks it will set a specific code in the TCM I don't believe the Preditor will get codes out of the TCM "you just get the TCM code P0700 just meaning there is a code in the TCM" Most programers that have a fast relearn will comunicate with the TCM and get you the codes and you can search on here and find pretty much any code you'll set.
Good luck,
Jon

got codes from it, dont know what it boils down to for whats really wrong with it though. 1st and reverse came back but MIL was still on, seems to drive just like normal again.

p0843 voltage from trans pressure switch to high for current operating conditions

p0733 incorrerct gear ratio condition in 3rd gear

p0700 turn on MIL light
p0700 trun on MIL light

i find it REALLY hard to beleive i limped it due to excess power, i was coming away from a light making a right hand turn pulling a 3000lb trailer, maybe 20% throttle tops after crusing the highway at 70mph for 15 miles till i got to my exit?? i was certainly not hot rodding it, actually i probly never hit over half throttle all day with it before this happened. i have mashed the peddle before in the past with this trailer on there going straight from a stop light and it never has slipped or acted goofy at all, just flat took off and hauled butt.

got codes from it, dont know what it boils down to for whats really wrong with it though. 1st and reverse came back but MIL was still on, seems to drive just like normal again.

p0843 voltage from trans pressure switch to high for current operating conditions

p0733 incorrerct gear ratio condition in 3rd gear

p0700 turn on MIL light
p0700 trun on MIL light

i believe the 0733 indicates you limped it... Mike or Eric will be more qualified than I to answer this..

I second the nsbu switch. dave

I second the nsbu switch. dave


what makes you guys think NSBU?? becuase of the shift range inhibit on the DIC or some other reason???

Incorrect ratio code, = limp usually.

I would guess c3 clutches are getting tired in that case.

With out doing some diag on the actual truck, hard to say if the 843 code is more cause or effect

ok, i follow the logic on the 0843 can equal limp and c3 could be whipped, but heres my problem with that theory. i was going from a dead stop after exiting the expressway way, what does c3 have to do with that and why would it limp 1st and reverse if 3rd was the culprit? plus i was not even working the truck hard at all?

well it ran fine on the way home, put the edge back on it, ran about 30 miles got it up into level five had the attitude set to show slip and lockup, did several full throttle runs got about .6% slip for just a split second when it locks up into 3rd then it goes right back to zero and stays there till the next shift. i have to beleive that the tranny is mechanically fine since i have never matted it so many times in level five from a stop and it ran perfect. i think it just had a computer hickup, or that pressure switch code caused it all to go crazy, maybe the switch is going bad and it will happen again, hard to tell but from the road tests i did the tranny seems to hold the power with no problems at all.

well it ran fine on the way home, put the edge back on it, ran about 30 miles got it up into level five had the attitude set to show slip and lockup, did several full throttle runs got about .6% slip for just a split second when it locks up into 3rd then it goes right back to zero and stays there till the next shift. i have to beleive that the tranny is mechanically fine since i have never matted it so many times in level five from a stop and it ran perfect. i think it just had a computer hickup, or that pressure switch code caused it all to go crazy, maybe the switch is going bad and it will happen again, hard to tell but from the road tests i did the tranny seems to hold the power with no problems at all.

do a boosted launch and see what happens.

If you haven't upgraded your transmission, it is NOT recommended you run the Edge above level 3. I run level 3 unloaded for mileage and level 1 for towing.

Mine would do the same thing before the trans upgrade.. Just cycle through or shut it off for a while.. Works every time.. haha.. After mine started doing it, it happened more and more often.. Trans time soon...

what makes you guys think NSBU?? becuase of the shift range inhibit on the DIC or some other reason???Sorry don't know why i posted that i musta been:drinking: . dave

well towed over well 100 miles today, never hicupped once. computer must have glitched somehow, thing runs like a champ again. just got to get the AC tuned up, its not cool enough. it was 90+ today at the race track and i had it on high and re-circ it blew cool but not cold after 50 miles i ill didnt need to turn it down.my '02 truck after 20 miles you had to turn the blower down or freee your butt off!!

Sounds like the multi funtion switch on the side of the trans.

I'll bet it limps again. P0733 is 3rd gear slip which means your C3s are very weak. TCM glitches do not throw slip codes. Your 2-3 shift is probably a little crisper now than before the code was set because the TCM now has bumped pressure to the C3 clutch.
mike

I think you need to listen to SMshiver... It is common knowledge that the clutches cannot handle the horsepower from level 4-5 unless you have an aftermarket torque converter. I think you are gonna loose that trans. On my 01 we lost the air recently and tried to do something similar to what we did at home when out compressor froze up. Turn the entire thing off (air) for 30 minutes and then turned it back on and all was healed.

Drew

I had mine act like limp mode, dealer said program glitch and stuck solenoid, after erasing the TCM codes, they said drive it and no problems since. I was towing a 4500lb boat, passed a couple cars on a 2 lane, but no tuner, all stock, and noticed it at the next town with a red light.