I am new to the group and am posting my first discussion. I am on my second truck and hace issues. My last truck was a 2001, 2500HD extended cab, LB7 with the Allison. The new truck (purchased in July) is a 3500 crew cab dooley LLY with the allison. now has 4k on the odometer.For a 51k price tag I was expecting to be Jazzed by the new LLY. The problems I am havig are very poor mileage towing my 12k 5th wheel camper. I get about 6 mpg towing , the engine fan noise makes you want to drive off a cliff, It lugs when coasting at about 1000 RPM, It has a distinctive growl coming from the engine when accelerating, It will stop when you back off the gas pedal. The wildest thing I have seen is that when I hitch my camper and pull it up the driveway and stop it bellows smoke that smells like an electrical fire (at first that is what I thought it was). So far I am not impressed!! I thought the LB& was a better truck. Any advise!!

If it were mine I'd be taking it into the stealer to have it checked. Especially with the smoke and smell and the growl from the engine. Hopefully you have a good service department to take it to. Mine has 15K miles and runs great.

the dealer did say to wait until the second oil change to see if any issues still remained. They are a top shelf dealer and I am confident they will fix the problem, It's just an aggravation to feel you took a step backwards on engine preformance

I heard several LLY guys needed a reflash?

kybones67, I purchased my LLY in June and had similar problems. I had the PCM reflashed last week and it made all the difference in the world. I no longer have the low idle surging and MPG's were markedly improved on my first check. The truck seems to move through the gear range smoother as well. Ask your dealer to reflash the PCM.

Like any first year production engine the LLY is going to have issues. To date they appear minimal compared to the LB7's during its first year. Good luck and Happy Holidays! JJ :)

I had the PCM reflashed last week and it made all the difference in the world. I no longer have the low idle surging and MPG's were markedly improved on my first check. The truck seems to move through the gear range smoother as well. Ask your dealer to reflash the PCM.


this is exactly what I have noticed since my reflash and reinstall of exhaust. runs smoother, more pep and pulled my trailer the other day very very easy versus before. injectors are not as loud either.

good luck