New GMC 2500HD 6.0 GAS Opinions

gamble77 · Apr 25, 2008

Am getting ready to purchase a new truck. I at one time had a 2003 Chevrolet 2500HD with the 6.0, I always felt like the motor had enough power but the 4-speed transmission just couldn't keep up. On the new HD's they have not only upped the power in the 6.0 engine but are now also putting the 6-speed transmission in them. Does anybody have any experience with this transmission? Any MPG figures? I don't think I can justify a diesel when you consider the extra money up front PLUS the extra money at the pump. Any advice would be appreciated.

AKfish · Apr 25, 2008

Hey Nathan, if it's the Allison tranny -- can't go wrong there; IMO. Don't know alot about the 6.0l engine. My younger brother has one that he tows his 7XX Bobcat with (can't remember if it's a 5,6,7 three series.)

His hasn't missed a lick! I think he get's around 12-13mpg pullin' a good load with it.

Best of luck.

AKfish

George2615 · Apr 25, 2008

I can tell you this. I have an 07 Duramax / Allison, 4x4, EC and since they added the diesel particulate filter the mileage is down. The 07 is 15.5 MPG vs. 20.5 for the 05 Duramax / Allison. Also diesel in my area is a buck more per gallon than gas. Mine is a lease so when it runs out I'll be going back to a gas truck unless they change something to improve the diesel mileage. Guy's I know with the gas trucks are in the 20 MPG range.

bdeboer · Apr 25, 2008

I test drove one about 2 month's ago and it felt like it had a lot more power than my '02 K2500 Suburban with the 6.0L. I researched the mpg. figures on another forum and they weren't that much better maybe 12/15. We decided on the K2500 CCSB Duramax/Allison and after 5,000 miles am seeing about 12/19. The 6.0L/4L80E used to try and overheat when pulling our 6,000 pound trailer, and I couldn't get excited about 6.0L/6spd. I haven't checked mileage on just towing yet, but am very happy with the way the truck went down the freeway with the travel trailer in tow.

KAB · Apr 25, 2008

It is actually a different engine than the older ones have. The new ones have Variable Valve Timing (VVT). Also, the new 6 speed tranny is not an allison but it is a GM 6L90. Lower 1st gear, 2 overdrives with the second being higher than the old ones overdrive. You can go here for more information: GM Media Online: English (make sure you pick the correct engine. In the tranny column you will see the 6sp tranny).

I have not heard any actual fuel economy numbers but I have heard positive feedback when compared to the old body style.

Kurt

cperky · Apr 25, 2008

I have an 07 chevy 2500 crew cab 6.0 with auto trans 4:10 rear end, utility bed, ladder rack 8' bed I can pull a trailer 80 down the hwy if I want but the mileage is about 11 mpg without a trailer, don't know what it is with a trailer.

I do have a pretty heavy load with all my tools and stuff in the utility bed.

Texashayman · Apr 29, 2008

I have a 06 2500HD 6.0 with a five speed and 4:10 gears that we use to run between fields with..been a great truck and pulls great (pulls 26 ft trailer, ford 3930 with front loader and large hay rake)

ihookem · May 2, 2008

You might want to look into an 05 or 06 with a diesel in it. I don't think the diesels are selling right now. I got 20.6 mpg hwy last week with my 05 Duramax but was going slow, 58mph. At 65 mph I would get 18-19 mpg. If you pull alot a diesel is nice. If you go with the 06 you get the 6 speed too with only a little more emissions.

Builder · May 3, 2008

ihookem said:
You might want to look into an 05 or 06 with a diesel in it. I don't think the diesels are selling right now. I got 20.6 mpg hwy last week with my 05 Duramax but was going slow, 58mph. At 65 mph I would get 18-19 mpg. If you pull alot a diesel is nice. If you go with the 06 you get the 6 speed too with only a little more emissions.

I would suggest that, too. Look for a 1-2 yr old diesel. That way you get the allison, and it will have a ton of warranty left on it.

Either that, or wait a little longer. GM will probably be installing the 6.2L V-8 with over 400HP for the '09 model year. It's already in the Tahoe.

jeffster · May 8, 2008

ihookem said:
If you go with the 06 you get the 6 speed too with only a little more emissions.

Actually, the additional emissions (DPF) didn't start until 07.5. I have the 06 LBZ Duramax with the 6-speed Alli and do not have the DPF. The 07 Classics don't have it either. Didn't start until the new body style 07.5 trucks.

Oh, and I love the duramax. Came from a 4.8 1500 truck and a 5.3 Suburban. I could tow them both at the same time, plus my tractor, and maybe the house too. heh.