In the market, have some Q's

[w_huisman]

I'm in the market for a Duramax. I've wanted to get back to a Chevy ever since I sold my 95 6.5TD suburban for a 03 F250 6.0TD, and now I'm ready to do so.

My budget seems to put me in the neighborhood of an 2003 to a 2006. What I'm seeing in my price range is the older vehicles with less miles, or the newer ones with more miles. More specifically, I typically see 03s and 04s with 80k - 90k miles, and a few 06s with around 120k miles on them.

I know the 06s came out with a 6spd auto tranny, and they'll have slightly higher performance numbers. Beyond that, what other considerations should I be aware of? Any years more or less reliable? Fuel mileage differences between years? Should I be looking for the newer truck with a few more miles, or the older truck with less miles?

One other thing...What are the major points of the typical factory warranty, or don't they transfer ownership past the original purchaser?

If this stuff is in a sticky and I missed it, feel free to flame the heck out of me.

TIA!

 

[BudTX]

I enjoy my Duramax (2004.5 LLY), but if I could go back and buy a brand new one from any year I would get a 2006-2007 LBZ. Besides the added power and the six-speed transmission, it is the culmination and correction of all of the defects and errors encountered during the development and production of it's predecessors, the LB7 and LLY. And no DPF!

 

[w_huisman]

How do I tell the difference between an 06 LLY and an 06 LBZ?

 

[BudTX]

Check the 8th digit in the VIN. If it is a D, it is an LBZ. If it is a 2, it is an LLY.

 

[RYDNHI4X4]

Like Bud said, go with the LBZ if your budget allows you to.

 

[RedneckBuckeye]

LBZ

 

[Mad Maxx]

Go with the LBZ, you'll love it.

 

[w_huisman]

I just heard that an 06 LLY is the exact same engine mechanically as the 06 LBZ, and the only difference is tuning. Is that correct?

 

[Mad Maxx]

I just heard that an 06 LLY is the exact same engine mechanically as the 06 LBZ, and the only difference is tuning. Is that correct?

As far as I know, yea.

 

[buddy]

I think the air intake is different, enhanced on the LBZ

The 04-05 LLY had a towing overheat issue because the intake would suck up hot air off radiator.

Older DMAX had injector issues, expensive if not warranty item.

 

[RYDNHI4X4]

What a lot of guys do is get the LBZ airbox and modify for their LLY's. Helps out a lot.

I think the air intake is different, enhanced on the LBZ

The 04-05 LLY had a towing overheat issue because the intake would suck up hot air off radiator.

Older DMAX had injector issues, expensive if not warranty item.

 

[BudTX]

Someone with a LBZ will have to clarify, but I thought that the LBZ pistons and rods differed from the LLYs as well...

 

[w_huisman]

I've got a bead on an 06 LBZ. Beautiful truck, but it's got 140k on the clock.

What parts should I plan on replacing if I buy a truck with that kind of mileage? Are there any drivetrain concerns at that mileage?

 

[BIGR]

Here is a bunch of reading on the subject.

Engine output for Chevy Silverado HD and GMC Sierra HD increased to 360 horsepower and a class-leading 650 lb-ft of torque.

Significant updates result in smoother, more refined operation, as well as reduced emissions New glow-plugs reduce start time by as much as 50 percent.

PONTIAC , MICH. - Later this year, GM Powertrain will introduce a new 6.6L Duramax 6600 turbodiesel V-8 (RPO LBZ) for the 2006 model year Chevy Silverado HD and GMC Sierra HD with class-leading horsepower - 360 (268 kw) at 3200 rpm and class-leading torque, at 650 lb.-ft. (881 Nm) at 1600 rpm. In addition to the power increase in the Silverado and Sierra, all 2006 Duramax engines have been significantly revised to deliver lower emissions and significantly improved quietness and smoothness in every application.

The 2006 Silverado HD and Sierra HD with the Allison 6-speed automatic transmission will be equipped with a significantly revised 310 horsepower Duramax 6600 (LLY) through the third quarter of 2005. It will be replaced in these applications in the fourth quarter of 2005, by the higher output, 360-horsepower Duramax (LBZ).

"The introduction of the Duramax diesel in 2001 represented a significant evolution in North American diesel pick-up truck market and propelled GM's heavy duty diesel pick-up truck market share to over 25 percentage points," said Charles Freese, GM Powertrain executive director, diesel engineering. "The introduction of the improved, 2006 Duramax turbo diesel once again sets a new benchmark to which all others will be measured."

The Duramax 6600's horsepower and torque increase and emissions reduction are enabled by a strengthened iron cylinder block and a lower compression ratio. The lower compression reduces stress on the engine by reducing the peak cylinder firing pressure. This, in turn, allows more fuel to be burned - more fuel means more power - while the lower compression helps reduce NOx emissions. Lower compression also helps reduce noise and vibration, making the all variants of the 6600 a quieter and smoother engine.

A revised variable-geometry turbocharger also enhances the driving experience of the Duramax 6600. Aerodynamic changes to the turbo's vanes help tailor controlled application of turbo power for seamless and immediate response at full throttle. The turbo, which spins at up to 120,000 rpm, is high-speed-balanced, reducing vibration and resonance - and contributing to the engine's overall smoothness and refinement. The revised turbo also helps reduce emissions, while maximum boost remains at 20 psi.

Another new feature of the Duramax 6600's turbo system is the capability of the variable-geometry turbocharger to provide exhaust braking. This function is available on some medium-duty truck models and can replace add-on exhaust brake hardware. With the new system, braking is controlled by a signal from the engine controller and can be activated by the driver.

The comprehensive list of changes and upgrades to the 2006 Duramax 6600 includes:

Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased horsepower and torque.
Upgraded main bearing material increases durability.
Revised piston design helps lower compression ratio to 16.8:1 from 17.5:1.
Piston pin bore diameter increased for increased strength.
Connecting rod " I " section is thicker for increased strength.
Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure.
Maximum injection pressure increased from 23,000 psi to more than 26,000 psi.
Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors.
Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions.
Improved glow plugs heat up faster through an independent controller.
Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions.
Air induction system re-tuned to enhance quietness.
EGR has larger cooler to bring more exhaust into the system.
First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions.
The Duramax 6600 also has a new intake air heater to reduce smoke and emissions during cold or light-load driving. The system features a 1000-watt grid heater located in the air intake duct, which is triggered automatically by the engine controller. It heats up the incoming air to speed warm-up of the engine.
In addition to 50 more horsepower and 45 more lb-ft of torque in the Silverado and Sierra, changes to the 2006 Duramax 6600 build on a host of improvements introduced for '05 - improvements that bolstered an already strong foundation. The Duramax 6600 features a rigid cast iron cylinder block with induction-hardened cylinder bores; four-bolt, cross-drilled main bearing caps; forged steel, nitride-hardened crankshaft; aluminum pistons with jet-spray oil cooling; aluminum cylinder heads with four valves per cylinder; integrated oil cooler and a charge-cooled turbocharging system. Features, such as easy-access fuel filter and timing gears, reduce maintenance time and effort.

A new, 32-bit E35 engine controller monitors and adjusts the engine's operation. Designed exclusively for the Duramax diesel engine, the controller helps the injectors precisely meter fuel to the cylinders and can compensate for the variability of the injectors and fuel flow. This sophisticated, more powerful controller also can support up to five injections per cylinder and eliminates the need for an engine-mounted drive unit to fire the fuel injectors.

The new Duramax 6600 in the Silverado and Sierra heavy-duty pick-ups will be available exclusively with the new Allison 1000 6-speed automatic transmission, featuring class-first features, like tap-shift range selection mode.

In addition to the Chevy Silverado HD and GMC Sierra HD, the Duramax 6600 (LLY) is also available at varying power outputs in the Hummer H1 Alpha, Chevy Kodiak and GMC Topkick. For 2006, the Duramax is available for the first time in GM's full-size vans, Chevy Express and GMC Savana, providing power and capabilities matched with quietness and smoothness not found in competitors' diesel-equipped vans.

The Duramax 6600 was introduced in 2001 and was developed in a partnership with GM Powertrain and Isuzu Motors. Since its introduction, more than 650,000 6.6L Duramax diesels have been built and sold.

The Duramax 6600 is assembled at the DMAX facility in Moraine, Ohio , a joint venture between General Motors and Isuzu created specifically to produce diesel engines.

2006 Duramax 6600 Specifications (LLY, LBZ) Assembly site: Moraine, Ohio.

Applications: Chevy Silverado and GMC Sierra 2500HD, 3500 pickups; Hummer H1, Chevy Express and GMC Savana full-size vans; Chevy and GMC medium-duty trucks.

Type: 90� V-8 charge-cooled (intercooled) turbodiesel
Displacement (cu in/ cc): 403 / 6599
Bore x stroke (in x mm): 4.06 x 3.9 / 103 x 99
Block material: cast iron with induction-hardened cylinder walls
Cylinder head material: cast aluminum
Intake manifold: cast aluminum
Exhaust manifolds: cast nodular iron with steel pipe extension
Compression ratio: 16.8:1
Valve configuration: overhead valve, four valves per cylinder
Valve lifters: Mechanical roller
Firing order: 1 - 2 - 7 - 8 - 4 - 5 - 6 - 3
Fuel system: direct injection diesel with high-pressure common rail
Horsepower (hp / kw): 360 / 268 @ 3200 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LBZ) (Automatic transmission only) (Available beginning 4 th quarter 2005)
310 / 231 @ 3000 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LLY) (Automatic transmission only) (Available through 3 rd quarter 2005)
300 / 224 @ 3000 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (manual transmission), Chevrolet Kodiak and GMC TopKick (LLY) and Hummer H1 Alpha (LLY)
250 / 186 @ 3200 rpm (Chevrolet Express and GMC Savana) (LLY)
Torque (lb-ft / Nm): 650 / 881 @ 1600 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LBZ) (Automatic transmission only) (Available beginning 4 th quarter 2005)
605 / 820 @ 1600 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (Available through 3 rd quarter 2005), Chevrolet Kodiak and GMC TopKick (LLY), (Automatic transmission only)
520 / 705 @ 1600 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (manual transmission), Chevrolet Kodiak and GMC TopKick (manual transmission) (LLY) and Hummer H1 Alpha (LLY).
460 / 624 @ 3200 rpm (Chevrolet Express and GMC Savana) (LLY)
Governed engine speed: 3250 rpm Silverado and Sierra (Heavy Duty), Kodiak and TopKick (Medium Duty) and Hummer H1 Alpha (LLY). 3450 rpm Express and Savana (LLY), Silverado and Sierra HD and 3500 (LBZ).
Crankshaft material/construction: forged steel
Connecting rods: forged steel, stress-fractured big-end caps.
Additional features: Turbocharger with charge cooling; exhaust braking (medium duty only); heated air intake; GM Oil Life System.

 

[btfarm]

I really liked my '05 LLY. I LOVE my LBZ! Like Bud said, all the major and minor issues were worked out by the release of the LBZ. I've got just about 90k on it, it's 100% stock and absolutely trouble free so far. Only thing to think about is leaky trans cooler lines on the '06 and '07 classics especially if you live up north. Other than that, they don't get any better. One thing to look for in a high mile truck is the average speed. Miles divided by hours. If it's over 40mph, it's over 85% highway and that's alot easier on it.

 

[Unit453]

I think the air intake is different, enhanced on the LBZ

The 04-05 LLY had a towing overheat issue because the intake would suck up hot air off radiator.

Older DMAX had injector issues, expensive if not warranty item.

The air intake between the 06 LLY and the 06 LBZ's are identical.

 

[Unit453]

Someone with a LBZ will have to clarify, but I thought that the LBZ pistons and rods differed from the LLYs as well...

No sir. Exactly the same, just tuning differences.

To highlight on what Rodney said, here are the main differences between a 2nd generation and a 3rd generation:

* Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased horsepower and torque
* Upgraded main bearing material increases durability
* Revised piston design helps lower compression ratio to 16.8:1 from 17.5:1
* Piston pin bore diameter increased for increased strength
* Connecting rod “ I ” section is thicker for increased strength
* Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
* Maximum injection pressure increased from 23,000 psi to more than 26,000 psi
* Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors

* Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions
* Improved glow plugs heat up faster through an independent controller
* Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions
* Air induction system re-tuned to enhance quietness
* EGR has larger cooler to bring more exhaust into the system
* First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions

The DURAMAX 6600 also has a new intake air heater to reduce smoke and emissions during cold or light-load driving. The system features a 1000-watt grid heater located in the air intake duct, which is triggered automatically by the engine controller. It heats up the incoming air to speed warm-up of the engine.

In addition to 50 more horsepower and 45 more lb-ft of torque in the Silverado and Sierra, changes to the 2006 DURAMAX 6600 build on a host of improvements introduced for ’05 – improvements that bolstered an already strong foundation. The DURAMAX 6600 features a rigid cast iron cylinder block with induction-hardened cylinder bores; four-bolt, cross-drilled main bearing caps; forged steel, nitride-hardened crankshaft; aluminum pistons with jet-spray oil cooling; aluminum cylinder heads with four valves per cylinder; integrated oil cooler and a charge-cooled turbocharging system. Features, such as easy-access fuel filter and timing gears, reduce maintenance time and effort.

Basically, the 3rd generations are much stronger motors. But as most of us know now, the weakest links in the DMAX design are the pistons. But under stock power levels, I've never heard of any that have failed.