Calling all Duramax/Allison owners

Silvertwinkie · 07-23-2004, 04:15 PM

I was wondering, I've heard all the great things about this engine/trans combo, but was wondering if there are any issues/problems that anyone has encountered...particularly with the newer engines that came out this model year (2004).

Any oil consuption issues out there?

Thanks in advance.

Cracker · 07-23-2004, 04:29 PM

Silvertwinkie:

I thought that you had gone with the Ford??? In any event, I've now rolled over 15,000 on my D/A, with quite a few thousand towing my signature AS, and I'm still in love! The dually is very stiffly sprung. Rough on secondary roads but a real joy on the interstate. Towing fuel consumption is about 11.5 mpg and non-towing about 17.5. Both of these figures are for mixed conditions but probably favor highway conditions. No oil consumption problems.

j54mark · 07-23-2004, 06:51 PM

I have the new LLY engine in my '04 2500hd 4X4. In 10,000 miles, it has needed only an oil change. Not only does it not use oil, the oil doesn't even turn black.

After repeated checks I can say I am getting something a bit better than 20 mpg in highway use. Just over 16 around town.

Mark

Pahaska · 07-23-2004, 10:07 PM

I don't have the latest version (missed it by a couple of months), but the engine/transmission combo is the best I have ever driven in a truck.

The transmission never has a hard shift when towing, regardless of grades. The shift-down of the transmission in tow/haul gives quite good engine braking for a diesel.

I get 19-20 when not towing and 15-16 towing the 25 Classic. I tow in OD with tow/haul engaged. On interstates, I sometimes can go for hours without it ever shifting out of OD.

Negligble oil consumption, never have had to add any in 12000+ miles, about 80% of that towing. Oil stays nice and clean. Seldom smell diesel fumes, only occasionally on wet morning starts and sometimes with wind behind at low speeds when the engine is cold.

Can't say I need the extra torque of the new version except for bragging rights.

Silvertwinkie · 07-23-2004, 11:36 PM

Thanks Cracker, Mark and John for the great input on the Duramax/Allison combo. I was a bit concerned about oil consumption, but I have yet to hear any real negs about the combo. I've been reading thedieselplace quite often and so far it's a hell of a ride.

Thanks again.

steelbird312 · 07-24-2004, 05:35 AM

Silvertwinkle,
about the only thing I could add would be that, of all the trailers Airstream offers, not a single one needs the dually for towing. The 2500 is a much easier ride, and with the D/A may be the premier tow vehicle. Mileage is great, and in my configuration, (crew cab/8' bed) it rides like a dream everywhere.
jerry

gklott · 07-24-2004, 07:45 AM

Purchased May 31, 2003. Now have >44000 miles on D/A, and > 25000 pulling Classic. Changing oil every 7500 miles per schedule, plus transmission filter. Following GMC service guide recommendations for scheduled maintenance, including complete transmission fluid/filter change at 30000.

Need to add about 1/2 quart between oil changes. Otherwise, no unscheduled maintenance required.

Mileage 10-12 mpg pulling Classic, and 16-18 mpg without. 1-2 mpg increase after adding SnugTop shell. Can highly recommend the shell for many reasons beyond the mpg increase.

Highly recommend the combo to anyone needing 3/4 ton tow vehicle.

73/gus

Silvertwinkie · 07-24-2004, 08:40 AM

Jerry/Gus...thanks!

Eric

Pahaska · 07-24-2004, 09:16 AM

The latest engine with 590 ft/lb torque only delivers full torque in gears 2, 3, and 4. Great for accellerating from a stop sign or climbing hills. In first gear and when cruising in 5th, torque is limited to 525#, same as the previous engine (mine). The 5th gear clutch pack in the Allison is the most critical part of the driveline and will not take repeated applications of 590# of torque. The first gear limitation may be more for limiting wheel spin or protecting other parts of the driveline.

**Pick** · 07-24-2004, 10:19 AM

I posted in your original thread, but in a nutshell, no problems in 10 mo., 22,000 miles. No oil consumption, using Mobil Delvac 1300 15W40.

Midamrail · 07-24-2004, 10:20 AM

My dad bought a used 2001 2500HD LT 4x4 extended cab with the D/A combo last year with 22,000 miles and then proceeded to put 70,000 miles on it in less than 8 months delivering trailers for an RV transport company. Despite the fact that over 1/2 of those miles were pulling 4K-12K pound TTs and fifth-wheels, he never had the first problem with the truck. In fact, beyond new tires and scheduled maintenance, he didn't do a thing to it. He totaled the truck in a bad ice storm while pulling a fifth-wheel through Wyoming but walked away without a scratch. We had the truck in our garage in St. Louis for a month while the insurance company figured out what to do, and despite the fact that the cab and bed were crushed, the truck ran perfectly even after a month of not running at all when it finally left on a rollback.

He averaged 13-17 pulling depending on the load and the conditions and 21-24 empty on the highway. We're Ford people, but that truck impressed us so much with its economy, stoutness, and comfortable ride that we're considering looking for a used one as a commuting truck from our rural home to the city.

silverback · 07-24-2004, 12:59 PM

Hi Silvertwinkie, Check out the Diesel Page Forums. I have read reports of problems with the new LLY engine. I have an early 2004 LB7 engine and have had no problems or oil use in 7100 miles (many towing the AS). I have been getting 12 - 13 MPG towing the 25' trailer and I'm not even close to being broken in. I also have a Snug Top Shell (UNI filter and Banks 4" Monster exhaust). The Allison transmission is amazing in tow/haul mode. That and the power extending tow mirrors have made towing fun.
Cheers,
Ken

j54mark · 07-24-2004, 03:52 PM

Quote:

Originally Posted by silverback

Hi Silvertwinkie, Check out the Diesel Page Forums. I have read reports of problems with the new LLY engine.
Ken

I have read of problems with the original Duramax. And the Allison transmission. And the GM manual transmission. And the 6.0 Powerstroke. And the 7.3 Powerstroke. And the 7.3 non-turbo Navistar. And the 24 valve Cummins. And the 12 valve Cummins. And others.

Mark

silverback · 07-24-2004, 04:06 PM

Quote:

Originally Posted by j54mark

I have read of problems with the original Duramax. And the Allison transmission. And the GM manual transmission. And the 6.0 Powerstroke. And the 7.3 Powerstroke. And the 7.3 non-turbo Navistar. And the 24 valve Cummins. And the 12 valve Cummins. And others.

Mark

Mark, It's probably a safe bet that the thousands of happy and satisfied LLY owners aren't doing a lot of posting. I'm glad to hear yours is solid.
Ken