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  • Giant Purple Snorklewacker

    Jan. 26, 2010 7:25 a.m. Giant Purple Snorklewacker SuperDork

    OK, having searched the earth for a big truck and driven a few... I have come to a decision.

    I am in the market for a Chevy Silverado / GMC Sierra 2500/3500HD 4x4 Crew Cab Short Bed NON-Dually Duramax with either an Allison Trans or a 6sp manual - the latter being unobtanium so really just a pipe dream.

    I see various ads touting arcane engine codes and large price swings between say '03 and '04 with the same mileage so... since one of you gentlemen/ladies is certain to be familiar with these...

    What model years do I want and what do I want to avoid? I am primarily searching for 2000-06 at the moment with less than 100k (financing/cost restriction...)

    Key points... my truck is an appliance, not a project. I have plenty of those already. I need to reliably move my projects to and from the track. I need to get to work/play/camping. I do not want to ever open the hood except to do regular maintenance. I drove the GM and like it better than the others so this thread is about the model listed above. I do not want to swap a Cummins into an F-250. I want to turn the key and go.

  • dinger

    Jan. 26, 2010 9:38 a.m. dinger None

    In reply to Giant Purple Snorklewacker:

    First, you can tell what engine you have buy looking at the ECU. It's located on the passenger side valve cover (or thereabouts).

    The 01-04 Duramax was the LB7 engine code. Early trucks had injector issues, which can be expensive since these are high pressure common rail diesel engines. Remanufactured injectors run about $300 apiece, which can get spendy. The 03 and 04 trucks seemed to have less issues with the injectors, and if you can find one with a good history of fuel filter changes you should be OK. Also, there is a 8 year/200K mile warranty on the injectors on the LB7 engines, so you don't have to worry much if you buy a late run model. These had a 5 speed automatic, and would tow in all gears.

    The 04.5-05 Duramax was the LLY engine code. These trucks had issues with injector clips coming off, overheating issues due to a new front end which didn't allow enough airflow (only when towing heavy, heavy, loads though 15K lbs+), are known for endlessly leaking transmission cooler lines, and were the first years for the VNT turbo, the EGR and catalytic converter. They had a slight horsepower bump but lost a little mileage due to the emissions junk.

    The 06 Duramax was the new LBZ engine. This motor came with a new front end for better airflow, the 6 speed transmission (Tow/Haul mode only uses 5), and the same emissions junk as the LLY. However, the 06 was still pre-DPF (diesel particulate filter) days, so the mileage hadn't fallen off like the current trucks. This truck has the most horsepower of all in your year range, for what it's worth - not that the others are lacking.

    All of these engines really like their fuel filters - I do mine every other oil change (about 10K or so) and it's $33 for a NAPA gold with the plastic housing, which you actually want over a metal ones because the metal ones rust out because one of the functions of the filter in a diesel is to separate water out of the fuel.

    Cliff's notes:

    If I were buying a Duramax today, i'd buy in this order: 1. 06 with the LBZ Engine code 2. 03-04 with LB7 and good service history 3. 04.5-05 with LLY that hasn't been worked hard

  • Giant Purple Snorklewacker

    Jan. 26, 2010 10:06 a.m. Giant Purple Snorklewacker SuperDork

    Thank you for the breakdown... so... it turns out one of my primary candidates is a late '04 LLY that does not appear to have towed anything. I have to look closer to see if its been painted but the hitch looks unused.

    Are injector clips a real problem? It sounds like something I can fix with a few $ and some zip ties.

    Is the mileage drop compared to the LB7 significant? 1 mpg city & highway isn't going to matter... but 5 would change my focus considerably. 99% of my driving is highway, whether towing or empty.

    Summary: If the price is right and I'm only pulling 9k lbs should I still pay careful attention?

  • dinger

    Jan. 26, 2010 10:14 a.m. dinger New Reader

    Chances are pretty good that the injector clips have been fixed already by a dealer. It's a real low buck fix, just a big pain in the rear when it happens when you are out on the road. The motor starts running rough and makes no horsepower.

    The mileage drop really isn't significant. Personally, I have an early 04 LB7. While it's the lowest horsepower rated, I enjoy the fact that it doesn't have a cat to clog up or an EGR to clean or replace. It also has a conventional wastegate setup instead of the VNT so if the turbo ever takes a dirt nap, it'll be cheaper to replace.

    That being said, if the price is right, that truck won't break a sweat pulling 9K lbs. There are a few easy mods to do to help it out in the cooling dept. that you can find online.

    http://www.dieselplace.com

  • unk577

    Jan. 26, 2010 7:21 p.m. unk577 New Reader

    I've owned all three. The 06' was definately my favorite. The 6 speed Allison is great. It was not uncommon for me to see 22mpg(unloaded) on interstate. Speed is critical, once i passed 72-72mph mpg would start to drop. The latest issue of DieselPower has quite a bit of Duramax coverage as well as the forum mentioned above. Early 06's had LLY's with the 6 speed Allison. The VNT is great, boost comes on quick. Banks makes a braking module that uses the vnt like an exhaust brake.

 
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