01-04.5 LB7 Duramax PowertrainDiscussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission Ect
My 01 will not switch into or out of tow/haul mode while moving. I have to stop for it to work. I don't think is normal is it? Also, a couple times while in normal mode I have come to a stop and it felt like someone hit me from behind. Like it surged just about the time I was totally stopped. But it felt it was bumped from behind. It's done that 3 times, but never consistantly. Any thoughts oh great duramax wise men?
__________________ 2001 Chevy 2500HD Durabliss Maximus Alisonious
You should be able to switch in and out of tow/haul at any point in time. Sounds like something is up with one of your computers on the truck. Maybe there is an update flash available? I would contact a local dealer and ask the service rep. Thats a new one on me.
As for the surge, it could be a late downshift to first, or the beginning of a converter failure. How many miles on your truck?
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Only 90,000 on truck. The late downshift sounds interesting, I guess cuz it seems like that may be what it's doing. But it seems to be already downshifted when it does it, I'll have to pay more attention. Like at a red light, come to a stop and then a second or 2 after it feels just like someone hit me from behind, lightly. It's done it a couple times, but not consistant. I had an 01 with the 8.1 gas and could switch in and out of tow haul on the fly so must be something switch related there. I was wondering if anyone is familiar with Camerota: Camerota :: Home
Have a few locations, and I could be at the NH one in under 2 hours. Anyone know of this outfit? Seems like a good place for Allison issues. Guess I'll call 'em up sometime.
Thanks guys...
__________________ 2001 Chevy 2500HD Durabliss Maximus Alisonious
My 01 will not switch into or out of tow/haul mode while moving. I have to stop for it to work. I don't think is normal is it? Also, a couple times while in normal mode I have come to a stop and it felt like someone hit me from behind. Like it surged just about the time I was totally stopped. But it felt it was bumped from behind. It's done that 3 times, but never consistantly. Any thoughts oh great duramax wise men?
My truck does the same surge sometimes. Sometimes worse than others. Some guys say thats a characteristic of the allison. I find that hard to believe. Ive had mine diagnosed by a transmission shop, and never found anything wrong. Plus ive had the filters changed with amsoil synthetic and it still does it from time to time. So it beats me. Maybe it is the converter
__________________ 02 chevy duramax, crew cab long bed LT 4x4 straight piped
PPE boost valve
My 01 CC dually does something like that every time i take off and stop. not quite sure, but I think it is the diesel sloshing back and forth in the fuel tank. kind of sounds like a bang or a u-jiont sound. hope this helps.
My '02 did the same thing, I was a bit lax then on servicing the Allison regularly. I now stay more on top of things with this '05 Allison, serviceing it more frequently done and I have never experienced it on this truck.
2006 Chev 6.0L/4L80e 3500WT DRW Ex-Cab, 9 'Flat/GN, Ride-Rite Air Springs, A/T Revos. Use-ta Haves 2005-LLY 3500 LS DRW Crew Cab, 2002-LB7 3500 LS DRW Crew Cab
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Last edited by Hook'em_Horns! : 07-22-2008 at 01:40 PM.
not sure what to tell you all but so far all the trucks mentioned are 01-02 LB7 with the 5SP Allison..heres a thought but if your NSBU switch is going bad it could cause those kinda problems but not saying thats what it is..other then that i'm out of ideas
__________________ James
TyreBoyz Pulling Team
Pulling Truck called Late Nights.05 LLY 3500 EC LB DRW tuned By Idaho Rob.
Work truck,06 LBZ 2500 CC SB SRW,tuned by Idaho Rob and PPE at times
My Truck now,1987 Chevy 2500 350 tweaked,6" SuperLift,350 V8 bored 60 over,Elderbrock headers Cam and Titanium Rockers,750 Twin Pumped Holley Carb and some other goodies.crank dynos over 400HP.
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