Home Forums Gear Hunting Trucks and Four-Wheel Drives Anyone here have a Duramax?

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Drive both trucks. You're in Colorado with mountains and killer altitude. So take the Dmax up a mountain grade, stop partway up then start again. You won't even feel the grade or the altitude. Then do it with the Toyota and feel how gutless that normally aspirated gas thing is. My Dmax is the same as the one you're looking at and it's the best vehicle I've ever owned. Tons of power, good mileage, rides beautifully, really enjoyable to drive.

Just purchased an 06 duramax dully.
The transmission shifts smooth, lots of power, feels like you are driving from your sofa. The tow/haul mode works really well - 14.8 mpg coming back from wasilla with a 14,000# trailer. It is a step up from my 97 f350 7.3 (edge programmer).

There's no comparison between the two. A friend with an '02/7.3 drove my LLY back when it was stock with just an 80hp tune, couldn't believe how much stronger it felt.

If your paying $60-$75 for oil then your running synthetic. I run Fleetguard Stratapores in my cummins which are propably the best oil filter you can run in one, just bought two the other day $18 for TWO. I run the 5 mic Baldwin fuel filter in mine $9. Air Filter also Balwin $20.

fuel filter for the tahoe I had cost more than the one for my cummins.

I've had 3 Duramax's, all have been good trucks. Currently drive a 2008 crew cab. The Duramax is a very good engine, and the Allison transmission is light years ahead of anything Dodge or Ford has come up with.

I get around 16 MPG on the dirt roads around here and 20 on the highway.

I'll agree that the Duramax has proven to be a good engine , but I fail to see what the Allison does that the recent model Ford or Dodge offerings don't do.......?

I'm new to diesels, is the duramax a Isuzu engine?

My father has a 2007 2500 CC Classic and he uses it pull his camper all over the place. I had a 2007 Dodge 5.9 CTD and I liked it and I now have a 2011 Ford 6.7 CC F250. In my opinion the GM has a winning combination. When I had my Dodge I was always jealous of the Allison and I towed with the Dodge and Chevy. The LB7 engines do have injector problems but in my opinion the 2006-2007 LBZ engine is the best diesel GM has made. The 2011-2012 also seem to be getting great reviews.

Designed by GM, built in a joint venture between GM and Isuzu.

No. It was designed jointly by Isuzu and GM, it's made in Ohio by Duramax. For this engine they started from scratch. They didn't adapt the engine from a tractor or dump truck. Bear in mind the American market is a small part of the diesel world as a whole. Isuzu has been making diesels for 70yrs or so. Depending on which year, they're the largest or one of the largest producers of medium and heavy duty diesel trucks in the world. They know what they're doing.

I'd only go there if one is happy with a short box. In my case, no.

here's food for thought, and this comes right out of G.M. Powertrane:

* prior to the 2005 there were three majore redesigns of the Duramax. 2004 was when they finally got off the pieces of the puzzel put together right. I'd avoid the very late ones as they had to choke the motor down to meet the ECM specs handed down by the EPA. At 118K the motor is about 1/3 of it's life span assuming it was taken care of.

* If the truck is an automatic, then crawl under the truck with a flashlight and look at the S/N tag on the transmission. It's an Allison, or a copy of an Allison. But they are different. Look for the numbers "933" on the tag. If they are not there, it's a Baltamore built copy. They are not made to Allison specs, and the gears are not all that great (still better than a Ford). Some trucks have an Allison tag on the fender. Forget this as an identifier!! If it has a real Allison transmission, it should last longer than the engine if taken care of.

Early Duramax deisels lasted about a week on the dyno, and usually suffered a catastropic block failure. The did a redesign of the block, and pretty much put that behind them. Then as power output grew; they started having problems with the head bolts pulling outta the block, and stretching almost a quarter inch. They did another redesign with bigger and better quality bolts with steel thread inserts. After that issue was solved the heads started to crack from the chamber pressures, and the heads were redesigned with more meat in certain areas. In the block redesign there was three phases, but only one hit the street. The blocks were actually blowing the complete bottom end out, and then some were splitting into two pieces. After that the bell housing flange was ripping off the blocks. (takes 70 hp. to drive the Allison gear box).

Sad thing is that in the test cell right next to it was a six cylinder Cummins that had about 765K miles on it without missing a beat! At about 800K they returned the motor to Cummins with a note on it saying it still was making good powder, and felt it was good for another 200K miles (pulling a 10K load). The six speed gear box was actually designed for Ford, and they were too cheap to put it in their trucks. So they simply changed the bell housing to fit the Duramax and the Cummins. They never were allowed to sell them to Dodge due to internal politics at Powertrane. Now Dodge is going to either use the Asian or a ZF transmission. The Asian is an AT542 built on license, and in many respects better than the LCT in the Chevy. The ZF is a good capable gear box as well. But in about three or four more years look for the Dodge to have a new 7 speed automatic built in the midwest unless they decide to stick with the others.

At about the sametime as they were designing the six speed; Ford sent in three trucks and several deisel engines ( Navstar). They were breaking one about every three weeks. Ford at first said they didn't have a problem (hard to work with). But each new engine shipment was a little different. After about 12 months they started to live on the dyno. Then they said they'd just build their own transmission. Shops love their 36K life cycle (average)
gary

Dodge and Chevy will be comming out with half ton deisels in the near future. They are talking 24 to 25 mpg in four wheel drive. The Dodge engine will also be built by Cummins, and has already been certified by the EPA. The Chevy engine is to be a scaled down Duramax, but with a different top end to get away from the problems with the current engine and the EPA. There's also talk about a smaller six speed auto that's completely different than the current LCT, and this one will probably show up in both trucks (not built by G.M.). But there's also some talk about reviving the original LCT (never went into production) and then the manufacturers will simply widen the frame about five inches total. This gear box has only three moving parts and is super efficent, but is about three inches too wide for the frames in todays trucks.
gary

actually your wrong. The Cummins with a strait stick is by a wide margin. I've been around just about every heavy duty drive trane made in the western world and a few from Russia and China. The Cummins 6 banger is the only engine we've not been able to completely break in that weight class.
gary

take this from the inside if you own a deisel engine:

* use Castrol deisel engine oil!! We ran tests on just about every one of them, and this is the best period

* quit buying cheap deisel fuel! Use something like BP or another premium brand (virtually all will gain fuel milage with BP). Stay away from anything that comes from Marathon / Ashland! It will ruin the top end of an engine in short order
gary

and all but two were clunkers. The 7.3 was the last good one they sold, and even it had some cheapo parts in it. That's why they and Navstar quit dealing with each other. Ford wanted cheap valves and a cheap injection system, and Navstar kept telling them it wouldn't last.
gary

I have 2006 Sierra HD that is pretty much as you described. This is my first diesel truck (many gasers before this one though).

I would go to the following forum site that has a lot of info on Duramax trucks and I found it very useful... (please forgive me if you are not to post other sites)

http://www.dieselplace.com/forum

Here are my PROs and CONs off the top of my head:

PROs
> great power and acceleration
>20% better fuel mileage (2006 diesel vs 2006 gas) - this no longer holds true with the 2011 with the new smog equipment and gasers now get 20 mpg due to shutting off cylinders
> Great for towing
> diesel tend to last more miles before major issues
> very easy to get a lot of power via a programmer (I keep mine stock)

CONs
> They ride very rough if you compare a 1500 vs a 2500 (especially diesels due to the weight of the engine up front). You have to have some weight in the bed to get a decent ride. I have a shell with about 250 to 500 pounds of stuff for a total of about 750 pounds, When I drove home with nothing in the bed you would think you just went 15 rounds with the heavy weight champion of the world.
> Cost - diesels generally start off costing 5k to 7k more than a gas engine
> Maintenance can cost more per visit (just look at you coupons... they always state excluding diesels)
> Everything that you replace on a diesel will cost more. Compare air, fuel, and oil filters.
> Diesel fuel is way more expensive per gallon than gas
> Tires are E range if you want to be able to tow and that costs way more than a 1/2 ton tires
> Fuel issues can be expensive... poor fuel, gelling, and the dreaded gas into a diesel (if you never had one before)

we need to have a long conversation about truck drive tranes! Yes there are differences, and some folks can't get the right parts for love of money because they are copyrighted. Torque convertors alone seperates the men from the boys here. Then there's the valve bodies. The Allison input shaft is made from strait 52100 Timken bearing steel; unlike the H13 crap that Ford and the Japs love so much. The splines on the Allison are rolled, and then induction hardened, and then finished after than. The others are cut splines that are far weaker in design. The gears are cut to about one fourth the tollerance that the Japs and Ford go by, and that makes them quieter and last longer. The involute is a well kept secret, and it's a light year better than anything on this planet. This list could go on and on!
gary

it's actually a joint design with Powertrane having the most input. Isuzu does manufacture it in Ohio. Their first choice was the Cummins, but Chrysler is the sole owner of that design (Ford wants it too)
gary