[TheFabricator]

Hello all. New to this site, not new to automotive stuff.

I have an '05 LLY, bone stock. On my way to work today I noticed that if I floor it, the engine RPM's will go up to about redline at 3k, then just kind of sit there, and not shift into the next gear.

While it is doing this, if I get off and back on the gas real quick, it will shift.

I have no DTC lights or check engine lights, no apparent other problems. Has anyone experienced anything like this?

Thanks in advance,
Albert Raczynski

 

[sheltonbh]

I also have noticed this on my 2004. Don't know why,....any one else???

 

[fast03]

I had this trouble with, but I was runnign stacked programs. without programs it still hangs some, but does shift.

 

[nextlevel38]

any codes????

 

[BudTX]

Is it cold when this occurs? I get this sometimes when first starting out, before the tranny has had a chance to warm up.

 

[TheFabricator]

No codes that I know of. No lights on the dash are lit up. It is cold out, but the car is certainly warmed up. Noticed this after about an hour of driving. Thanks for the quick replies so far.

 

[fast03]

no codes for me either.

 

[TheFabricator]

Now today and later last night it didn't do any of the non-shifting.... does this seem strange to anyone?

Yesterday was about 15 deg outside, today is about 25 deg... I can hardly imagine that would make much difference.

How does the trans act if it goes into limp mode, i.e. when you are developing more power than it wants to see?

 

[mukmow]

hi all just joined due to this problem also!!. have 220,000 kms (136,000 appx miles) on my 04 2500HD not sure if mine is a LLY or not will check tomorrow in daylight. had to have the seals in the allison replaced around 140,000 kms. never did seem to shift as smooth as it did before the seal change. dealer says everything is okay when i took it back to them after the change out. now this!! really scared the crap out me when your in the middle of a pass and the thing goes flat.

outside temp was around 0C ( 32F) and the truck was warm. middle of a 4 hour drive this time.

 

[03LB-7dmax]

Now today and later last night it didn't do any of the non-shifting.... does this seem strange to anyone?

Yesterday was about 15 deg outside, today is about 25 deg... I can hardly imagine that would make much difference.

How does the trans act if it goes into limp mode, i.e. when you are developing more power than it wants to see?

Your not in limp mode! you would see SES light, and SHIFT RANGE INHIBITED on the dic. Had the same problem, I changed my fuel/tranny spin on, and the problem was gone. But I think it was the fuel filter, as it happened again 12k later, just did the fuel filter again, and it was gone.When was the last time you changed it?