I can get a 04 Duramax extended cab 4x4 it's a SLE Sierra short bed. It only has 40, 000 miles on it. Sense i work at the Dealership they will sell it to me for $21,000. It has bald tires and the passenger doors have a bunch of touch up paint so i would have to re paint them. The truck is all stock other than it has the muffler taken out and straight piped. I checked the 8 digit of the vin and it's a 2 so it's the LLY 04.5 i heard these are the better ones and shouldn't have injector problems. I plan on beefing it up adding an exhuast, intake, chip, and ect. Will a duramax hold up with some of these mods? I heard they will blow head gaskets or it is common for them to go around a 100,000 miles. What year did they go to the 6 speed auto tranny's? I be leave the 04's are the 4 speed if not correct me. I really would like to get a cummins, but i can't find any at a good deal and the Duramax should ride better with the IFS. So what's your opinion?

 

the LLY has less injector problems, but it has over heating issues when worked hard while towing

you can do all your mods but you're going to have to plan for transmission upgrades as well, the stock Allison doesn't like to be beat up on with a tuner

the A1000 in the 01-05 trucks is a 5 speed

 

there a few random mishaps with lly HG. not very common though. In order to overheat the lly you really have to use it like your are supposed to which hardly anybody does.

stock trans can take a tuner. depends on how big you want to go, a lot of tuners you can buy can hurt the trans if you turn them up high enough.

 

So the tranny is the only thing to worry about? That's good because i don't want to change injectors or a turbo. How much would it cost to make the tranny hold up to a 100+ hp tune? How do i keep the EGT's down if i run over a 100hp tune? What's the highest your EGT's should safely get?

 

if you are going to tow replace the factory turbo mouth piece with a lbz or kodiac type, the factory tmp is too restrictive. the stock tranny will handle 100 extra hp, just take it easy with the 4th to 5th and 5th to 4th gear changes. replace the exhaust to rid the cat, turbo down pipe, and i'd get a set of boost and pyro gauges to keep an eye on things. as far as egt's go, i'd say just don't let it see 1400 for more than trip down the track.

 

So replace that turbo mouth peace and keep an eye on the gage's. The EGT's shouldn't get hot unless i am towing heavy or beating on it hard right? How will the EGT's hold up for a longer trip like a 4 to 8 hour trip? Some one said just click the over drive off if you run it hard and they will help your tranny last. Then once your out of the throttle click it back into overdrive. I found a 06 crew cab is there any advantages of going with a 06 other than moving to a 6 speed tranny? Will the 6 speed hold up to more power?

 

gm specs the engine can hold 1350* sustained.

the 6 speed auto will hold more power, and if you add a transgo to it you can hold even more. it wont be a stupid fast truck, but running mid 13's is achievable with stock trans and it holding up with no issues.

 

I love my 06, has all the issues of the 04.5LLY fixed, the only minor thing is the pistons like to crack under intense fuel and timing, but if you run a mild tune with low timing you will be just fine, there are issues with headgaskets on 06's, but they aren't that common

 

i have an 05 with and i love it plenty of power towing with just a straight pipe and an intake. i also have efi life but i dont hammer on it. agreed on the mouth peice its the first mod i made before efi live.

 

i have an 04.5 lly. havent had any major trouble it is. all minor junk but i picked it up for $17000 with 150000 miles. since i bought it here in texas, i have driven it to ohio (my home town) and back to texas 4 different times. During those trips i never shut the engine off. even to fuel up. This truck is a freaking tank. never stops chugging along. when it comes to mods...... i have done the kodiak mp (i feel its the best bang for ur buck) and it doesnt come with resinator port so u dont have that pesky turbulance in ur intake. I have also cut the catiletic converter out and welded in a straight pipe for a wee bit more response out of my turbo and it makes a nice turbo whistle now. i plan on cutting the muffler out and going straight pipe with a 4 inch tip for *****. also i have cut my stock air box for better flow into the box. re-routed my PCV so i dont have any more oil blowing into my intake to F up my intake system. Also bought cheap tuner off craigslist. added about 80 more HP and 120ish TQ, and about 2 MPG. (these are my oppinion, take what u want and what u dont want just ignore) other mods that are musts for me,....EGR blocker with finger stick, banks cold air intake with scoop, banks intercooler kit, 4inch dual exhaust MBRP, New down pipe off the turbo, PPE exhaust manifolds with turbo up pipes, PPE intake manifolds with inlet pipe. PPE or ATS transmission rebuild kit. PPE HOT+2 tuner, PPE HD ideler arm and pitman arm. FabTECH HD tie rods, Rough Country 6inch suspention lift, New Rims with 35ish inch tires, Alien Patrol front and rear replacement bumpers, and a list of other junk

All the parts total up to about $30,000 dollars installed. good thing its a diesel and it will last long enough for me to do all the work i want