Any LB7 Duramax guys here?

[Ujaiaso]

Hey all. I have a 2004 Silverado 2500HD 4x4 with the LB7(?) VIN#1 Duramax. Owned it for about 6 months now and now matter what we do to it the truck throws trouble codes for the mass air flow sensor and the egr system. It's been to Chevy 2 or 3 times now and both the entire EGR and MAF systems have been replaced but the trouble codes always come back after about 20 miles of driving. There is a K&N intake on the truck but Chevrolet insists that it has nothing to do with the issues I'm having.

Aside from that what kinds of trouble can I expect from the LB7 and the Allison 1000? Both Chevrolet dealers I've had the truck at have mentioned that these motors were problematic from the get-go and should be avoided, wish they'd have told me that when I bought it...HA! I have had a bunch of issues with the fuel system losing prime(random loss of power and stalling) and the trans going into limp-mode.

 

[True Grit Farms]

http://www.trucktrend.com/how-to/transm ... -disaster/
You will have this problem, and if not noticed early it'll cost you. I thought the injectors were the weak link on those model. The front hubs and all the steering components are not real great either. A GM with the Duramax is the highest maintenance light truck package available. Good luck.

 

[Atimm693]

Hey all. I have a 2004 Silverado 2500HD 4x4 with the LB7(?) VIN#1 Duramax. Owned it for about 6 months now and now matter what we do to it the truck throws trouble codes for the mass air flow sensor and the egr system. It's been to Chevy 2 or 3 times now and both the entire EGR and MAF systems have been replaced but the trouble codes always come back after about 20 miles of driving. There is a K&N intake on the truck but Chevrolet insists that it has nothing to do with the issues I'm having.

Aside from that what kinds of trouble can I expect from the LB7 and the Allison 1000? Both Chevrolet dealers I've had the truck at have mentioned that these motors were problematic from the get-go and should be avoided, wish they'd have told me that when I bought it...HA! I have had a bunch of issues with the fuel system losing prime(random loss of power and stalling) and the trans going into limp-mode.

There is an electrical problem, and the dealer just doesn't know how to diagnose it properly.

They will have more problems and require more maintenance than a 12V Cummins, for example. These trucks are getting old, and they're very complicated. They're also quieter, more fuel efficient, and more powerful than a 12V, it's a trade-off.

The transmissions are programmed to shut down when slippage occurs. The issue is a lot worse when you have a tune.

 

[littletom]

Look up dura max forums

 

[Brute 23]

Remove the k&n and clear the codes. See what happens.

Hopefully that truck wasn't deleted and then they tried to put it back to sell.

 

[jltrent]

Neighbor has a 2002 with a straight shift. He has had pretty good luck, but the injectors have been replaced and he said acting up again.

 

[hurleyjd]

You might remove the connector to the computer and clean the socket and plug. 2005HD Gasser here that was the problem after replacing everything that they thought was the problem. They would clear the codes and after several minutes the codes were back. They plugged the plug to the computer and cleaned it and the connector and now the codes do not show.

 

[Bovine breeder]

Hey all. I have a 2004 Silverado 2500HD 4x4 with the LB7(?) VIN#1 Duramax. Owned it for about 6 months now and now matter what we do to it the truck throws trouble codes for the mass air flow sensor and the egr system. It's been to Chevy 2 or 3 times now and both the entire EGR and MAF systems have been replaced but the trouble codes always come back after about 20 miles of driving. There is a K&N intake on the truck but Chevrolet insists that it has nothing to do with the issues I'm having.

Aside from that what kinds of trouble can I expect from the LB7 and the Allison 1000? Both Chevrolet dealers I've had the truck at have mentioned that these motors were problematic from the get-go and should be avoided, wish they'd have told me that when I bought it...HA! I have had a bunch of issues with the fuel system losing prime(random loss of power and stalling) and the trans going into limp-mode.

Your truck isn't an LB7. The EGR system wasn't added until the LLY engine code in 2004.5. If you pop the hood, you'll see the LB7's have Japanese IHI turbos. The LLY's have Garret Variable Geometry turbos. The injectors are one of the only weak spots on either engine code. Some LLY's had head gasket and overheating issues. Overall they're phenomenal trucks. I've had my LB7 for 8 years

 

[aayjay]

Hi you must have a California emissions lb7 like mine. I had the same issue and found a post that said it was the vacuum pump. Mine was actually making noise you could only hear standing in front of the truck. Replaced it and no issues since. Little bit of a pain to get to the three bolts but not too bad. Good Luck.

Google lb7 vacuum pump. The site was yellow bullet something.

 

[ShrikantPillay]

I was facing the same issue, thank you for the help..