Buying a Used Duramax/Allison

TheTrueMoron · April 15, 2014

Hello,

I am considering trading in my 2011 1500 Z71 for an older (05+) Silverado or Sierra 2500 with the Duramax/Allison package. I've been looking at several, usually with 120,000-150,000 miles on them. A few of them are lifted with bigger tires. I'm just wondering, what disadvantages would this pose? I know the truck will have more wear and tear, but how much longer will the drive trains last? Am I at risk of more issues? If I trade, my monthly payments would come down $150-200/month, and I would have it paid off a year or two sooner. I'm also considering having this larger truck so that I could do some side towing gigs for some extra money. Basically, is it worth it? Thanks!

Danthaman69 · April 15, 2014

The LB7 and LLY motors are the best. Very dependable trucks 2 of my buddies have well over 200,000 miles.

I'm looking buying for work myself. Of course I'm tuning it for gas mileage.

STINSAN3 · April 15, 2014

Thats a good question.

Prokopchuk_9 · April 16, 2014

Lb7's have injector problems, LLY has overheating issues. Look for an lbz

kstruckcountry · April 16, 2014

If it lowers your payments, and you like driving it I'd go for it. But since you're not pressed for time you can be really picky, which you should do. Get exactly the truck you want, if it was me I'd get an LBZ (06-07 classic). They're great motors. Lower fuel mileage than a half ton in some cases, but can tow just about anything. Your oil changes will be bigger but you can run it a long time. I wouldn't want to buy a lifted one, especially towing in mind. You can tell looking at it and driving it if it's been babied or thrashed.

02suburbanZ71 · April 16, 2014

06-07 classic LBZ with allison. Thats probably what you want for 150K miles

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06_GMC · April 18, 2014

Here's the thing. The LB7 just needs to have something like a FASS system put in it and bye bye injector issues. The LLY needs head gaskets over time but most diesels shops will fix it right for around $1100. LBZ's are great but also cost a lot more. One because everyone wants one and two because they were only offered in 2006.5- 2007 trucks and only the classic style for 07. Any of them would be great. I personally will probably be looking for an LB7 with fresh injectors and I'll throw a FASS system on it. I would get the nicest untuned and un modded truck you can find for your budget and just have some money set aside in case it needs some minor repairs.

Prokopchuk_9 · April 18, 2014

Here's the thing. The LB7 just needs to have something like a FASS system put in it and bye bye injector issues. The LLY needs head gaskets over time but most diesels shops will fix it right for around $1100. LBZ's are great but also cost a lot more. One because everyone wants one and two because they were only offered in 2006.5- 2007 trucks and only the classic style for 07. Any of them would be great. I personally will probably be looking for an LB7 with fresh injectors and I'll throw a FASS system on it. I would get the nicest untuned and un modded truck you can find for your budget and just have some money set aside in case it needs some minor repairs.

Filtration will prolong it a little while, that's not the problem. The issue is a design flaw with the injector cups, it's not a matter of "if" you will ever need to do injectors it's "when". A lift pump might help, but 90% of guys say it doesn't do anything. Some last 200 some last 50, it's a crap shoot.

LLY's don't have head gasket issues, they have overheating issues. It all stems from a faulty intake/mouthpiece design. All you need to buy is an LBZ turbo mouthpiece or an AFE one and a CAI. Also the injector harness rubs on a couple injectors and you'll end up with some weird injector issues. All you gotta do is the ice pick fix. Everybody is afraid of LLY's but they are decent, I wouldn't be afraid of one.

LBZ cost the most because they don't have a DPF, classic style and have a 6 speed allison.

mike94silverado · April 18, 2014

I'd be looking at the RV dealerships.... seriously, find one that the "old Guy" owned and took care of not one that a younger guy (admittedly like me) modded.....

hockeypro1411 · April 20, 2014

The LLY overheaters are the guys pulling 15k through mountain passes in July. The VAST majority of LLY trucks never have an issue with it. There's nothing to be afraid of with them, really. The 6 speed Allison versus the 5 would never be a selling point to me. If it has it, sweet. If not, sweet. Naturally that's biased because I love my LLY, but you really can't go wrong with a 120k-150k Duramax that's been properly maintained anyway. Happy searching!

I included a picture of my LLY. Never before seen on GMT.com!