I just bought a 05 C4500 with the Allison auto. Not sure if the 4500 has the same tranny as the smaller trucks, but I would like to add some more towing power to the truck as I haul a 40' Carriage 5th wheel. My 99 F-350 used to pull it down the highway easy as you please, {but was modded pretty heavily} 402 HP and 802 TQ. I would like to bump up the Chevy, but with the automatic, I sure don't want to find out how much a new one would cost.

my tranny holds 50 and 70 extra hp ok. the 90 and 150 settings on the bullydog worry me too much, the 150hp is waaaaaaaaaaaaaaaay too much power.

He has a LLY 4500 remember. If I were you I would give Steve Cole a call at TTS (goes by diesel tech here) www.ttspowersystems.com (http://www.ttspowersystems.com/) is his website. He may be able to spit you out a smaller custom tune that gets around some of the different quirks the 4500's have IIRC. Dont they have different limiters ect? I'm almost 100% positive the programing isnt the same as the regular trucks.

Thanks for the information. I know of Steve Cole from a different web site I used to frequent when I had the PSD.