2005 duramax lly gas mileage/ power question??

[duramaxed]

I recently purchased a predator U7185 for my 2005 chevy 2500HD with a 6.6l duramax lly and was wondering which setting would be the best for fuel mileage as I have ran it on the 65 hp economy tune for the week that I have had it and it seems like the mileage is worse than it was at stock and also what would be the safest high hp setting to run on a stock tranny with 115,000 miles on it. Any input is appreciated thank you.

[troy.bushley]

I am wondering about the same thing. I have recently installed 285 series tires and reprogrammed th eutner to reflect the new tire size. I am currently running 80 hp tune and seem to be getting about 16-18. I think it should be better than that. Hoping someone has figured this issue out and can help us.

[mikel]

Many people like the highest tune for mileage if they can keep their foot out of it.

[duramaxed]

I ran the 80 HP tune for a week or so but I think I limped the tranny is that common for it to limp it on the 80 HP Tune I had read a lot of things saying that I should be ok up to 100 HP over stock. I turned it back down to 65 but want to turn it back up is there anything I should check out to make sure my tranny is ok? Thinking about getting a Transgo jr would it help to hold the higher HP tunes?

[duramaxed]

I found out that you can not get a transgo Jr. For my year truck so is there anything else that I might be able to do, I would like to be able to run the 80 HP tune but it has limped my tranny 3 times, I am not sure if it is coincidence or not but the first time was the same day I had my cat and muffler cut off, could the EGR codes have something to do with it and if so any suggestions on what I can do to block them?

[BuxDmax04]

I run the 100hp tune in my 04.5 LLY Dmax. I ran it through a unofficial quarter mile the other night. The truck reached the 100mph mark before I hit the quarter mile mark. needless to say I was thrilled. However about the same time I hit 100mph, the tranny also shifted into 5th/OD gear. The truck shuddered and the CEL came on. I immediately slowed down but, as I was driving away I noticed the truck was shiftung wierd and it acted like it had a lot less power. I figured that I had caused the truck to go into "Limp" mode. I'd read about this happeneing to guys with a 100hp or more tune over stock with a stock allison tranny. I pulled out my Diablosport Predator and read then erased my DTC code the truck had popped. The code was a P0700 (transmission control system fault). After I erased the code, i took my truck for a test drive and it was all back to normal. My question is would selecting OD off, with the switch on the end of the auto tranny gear shift lever, prevent my truck from going into limp mode when I hot rod it? It really did appear to go into limp mode immediately after shifting into 5th/OD gear with my foot still on the floor. i would eventually like to take my truck to a dragstrip and make a few runs to get an official quarter mile time and speed but, I don't want to cause my truck to limp, again. It just seems logical to me that since the truck faulted for a tranny problem as it shifted into OD with my foot on the floor, that turning OD off would prevent this from happening again. Please let me know what you think. Question number two is: I get an average of 23mpg during mixed city/highway driving with the 100hp tune, would installing the 65hp economy tune get me better mileage? You definitely hit the nail on the head with your earlier comment. I too, get great mileage with the 100hp tune as long as I can keep my foot out of it...hehe...but it is so much fun to "not" keep my foot out of it.

[BuxDmax04]

I just read the top and wanted to give you all of the rquired information for you to best answer my questions.

Make: Chevrolet
Model: Silverado 2500HD
Year: 2004...2004.5 actually
Engine: LLY Duramax Diesel
Tranny: Allison 1000 5spd Automatic
Predator: u7185

[booger]

using just the t/h button doesn't limit the truck from going into 5th gear, you must select the 5th gear in manual mode 4th, the tranny will still change gears, but keep the truck out of 5th. the weak spot is the 4 to 5 and 5 to 4 gear changes in the ally. also, once you have limped the tranny it becomes easier to limp it again, if you want to hot rod save up for a tranny build and you willhave no worries.

[hardcore_defee]

What kind of times in the eighth of the mile are you gettin out of these LLY motors wid just the 100 hp tune. im new to this . just curious . i have 2005 2500 crew cab 4x4 . and i tried to install the tuner and it fried my ecm or locked it and the hand held up has any one had this problem