I drove a friends new 2008 2500HD with the 6.0 in it today for a few miles. It was definately different with the 6 speed tranny compared to the 4 speed. I don't know if it really seemed like it had more power or not, but when I floored it, it really sounded pretty good. He told me so far it was only getting maybe 0.5-1.0 mpg better than his previous 2005. I figured the 6-speed would've helped more. For those who went from the 4L80E to the new 6-speed, was it worth it? Just curious.

This could be a great engine and trans combo, but GM's got the programming set up so d**n conservative that it doesn't react the same way twice, or allow the truck to do all it can do, (sounds like a commercial for the Army).

I've had a custom tune put on my truck and now I know how it'll react each time, but my tuner can't eliminate the delay at 20mph and 35mph when you nail the gas - it's real noticeable in traffic when you see the lane next to you is empty and you need to get in there fast. You just need to allow for the delay and react sooner.

I drove a friends new 2008 2500HD with the 6.0 in it today for a few miles. It was definately different with the 6 speed tranny compared to the 4 speed. I don't know if it really seemed like it had more power or not, but when I floored it, it really sounded pretty good. He told me so far it was only getting maybe 0.5-1.0 mpg better than his previous 2005. I figured the 6-speed would've helped more. For those who went from the 4L80E to the new 6-speed, was it worth it? Just curious.

If his truck is new,it needs to break in and loosen up a bit,and it will improve.Give him 2 or 3 oil changes,and see what its like then.Also a new truck tends to get run harder until you get used to it,IMO.Once the newness wears off,the foot gets lighter.:D With the 6speed autos,they are a great trans for towing,but running around empty,give me a 4 speed auto any day.The 6 speed has to shift to many times,and if you need a kickdown,its got to drop 2 or 3 gears before you can get going,add the torque management to all those shifts,and IMo it is a disaster running thru the gears empty,and trying to get a kickdown to pass.

It's definetly different. If you think you like the old 4 speed, simply put the gear selector at "Manual 4". The truck will shift up through 4 gears, and no higher. I tow most of the time. I use manual 4, and manual 5, depending on the roads I travel. If your thoughts are trading up for the purpose of the new 6 speed transmission, your wasting your money. For me, I was upgrading all the way around. I,ve driven them all over the years, but always favored GM trucks. Let me tell you this; I really liked the dodge, with cummins diesel, manual transmission. Gas & diesel prices started sky-rocketing. I went with GMC due to the fact that I stayed with gas engine. Don't get me wrong; I like my GM truck. It's a nice truck. So far, very dependable. If it wasn't for towing every day, up and down many hills, I'd say it was the perfect truck. Since I do tow most every day, up and down hills, I cant get that dodge, with cummins diesel, manual transmission, out of my mind. On average roads, my GMC doesn't even know it has a trailer hitched. 10.5 MPG towing. last I checked, 14.5 not towing, but loaded.

It really needs a blower. Without the 8.1, GM really needs a more capable gasser for their 3/4T trucks.

I drove one at work a couple of weeks ago, and I was impressed.

I didn't drive it very far, maybe 10 miles at the most. Got on it a couple times. It only had about 5000 miles on it, so it probably still needs to break in a little yet. I'm not looking to upgrade anytime soon, I was just more curious on how people were liking the new setup. If I do anything it will be a custom pcm tune to get rid of some of the TM. I have drug my feet though because I occassionally tow heavy and don't want to damage my tranny as the cost of that would outweigh the benefits of a tune. The constant shifting is definately something one needs to get used to. My 4-speed never downshifts unless you're going up a huge hill bucking a wind. However, I've gotten somewhat used to a 6-speed as my wifes Acadia has a 6-speed (albeit completely different animal). That thing shifts all the time. Any small incline and it downshifts to 5th. I'll be interested to see how the tranny's hold up on these vehicles. I think the 6.0 is one very capable engine, but do you think GM has any plans of bringing out another gas option like a 7.0? Just curious.

I wouldn't expect anything bigger in a truck because of emissions-that's why they quit with the 8.1. They had to meet stricter emissions standards and the R&D money/results required to do that on the 8.1 made it not reasonable.

But then again, the LS7 in the Z06 Vettes is a 7.0...

I wouldn't expect anything bigger in a truck because of emissions-that's why they quit with the 8.1. They had to meet stricter emissions standards and the R&D money/results required to do that on the 8.1 made it not reasonable.

But then again, the LS7 in the Z06 Vettes is a 7.0...


Haha that would make for a fun truck:D

On a more serious note, I realize why the 6 sp shifts much more then the old 4sp but since i live in ND there are not a lot of hills. What do you think the milage would be driving around 65? I was thinking 16-17 but was hoping for a little more ecspecially after a good tune. Maybe 18?

My cousin has a 08 2500Hd with the 6.0 he says it only gets 11Mpg empty and 8mpg Towing. It sure doesn't tow good either I didn't want to embarass him by asking him if he wanted me to tow his jeep so we could not go 50 up all the hills.

My cousin has a 08 2500Hd with the 6.0 he says it only gets 11Mpg empty and 8mpg Towing. It sure doesn't tow good either I didn't want to embarass him by asking him if he wanted me to tow his jeep so we could not go 50 up all the hills.

Something seems to be off there unless it is 100% city

Something seems to be off there unless it is 100% city

Probably Phoenix is a Conrete jungle

Probably Phoenix is a Conrete jungle

That would explain it:D

I love my truck. I did not really know at first how much I liked the Hydra-matic 6 speed, but I actually began to really like it once I got use to it. There are times I do not like how the transmission down shifts two gears, but it is not a big deal to me. My truck seems to have plenty of power for me, but I do not tow very heavy loads either. Most of the loads my truck would see are in the bed, and the only thing I have to tow right now is a cement mixer.

6.0L is a solid engine (far better than the Ford 5.4 in the SD's) and my choice. However, I'd like to know why we don't get the 6.2L instead. The extra 40bhp/30lb/ft sure would be nice. If anyone knows please pipe up...

6.0L is a solid engine (far better than the Ford 5.4 in the SD's) and my choice. However, I'd like to know why we don't get the 6.2L instead. The extra 40bhp/30lb/ft sure would be nice. If anyone knows please pipe up...

I'm not sure, but i would like to know as well, maybe the torque curve is much to high? i have no idea

the new 6 speed is good if you want to tow more then drive around empty. i hate the way it shifts. you can feel it down shift and there is a kick from 2nd to first. better to stick with the old 4 speed

My truck when on an on ramp if I punch it it will fall on its face down shifting. I get 14 MPG avg. Over all its been a good truck with 67K and counting on oil field roads.
Any one know a trick to get the exhaust to seal up after you bend it? Repair shop installed a new ring but it only lasted one week.
Starting to get loud enough that the radio will hardly cover it up anymore.
Sorry don't intend to hijack.

6.0L is a solid engine (far better than the Ford 5.4 in the SD's) and my choice. However, I'd like to know why we don't get the 6.2L instead. The extra 40bhp/30lb/ft sure would be nice. If anyone knows please pipe up...

a lot of it is because of marketing...they want to reserve the best stuff for the Cadillacs/Denalis-why else would you buy one if they were the same as the rest.

You can get the 6.2 in the Tahoe LTZ for 2009.

The 6.0 is a good powerplant that is sturdy and less "complicated" than the 6.2 also. That's what you need in an HD.

a lot of it is because of marketing...they want to reserve the best stuff for the Cadillacs/Denalis-why else would you buy one if they were the same as the rest.

You can get the 6.2 in the Tahoe LTZ for 2009.

The 6.0 is a good powerplant that is sturdy and less "complicated" than the 6.2 also. That's what you need in an HD.

Good response. Marketing is all I could think of too. You also make a fair point in talking about it being less complicated, that's certainly important. Just a shame as 360/375 is plenty but 400/415 that bit nicer:D

even the new H2's are getting the 6.2

even the new H2's are getting the 6.2

So are the half ton trucks in LTZ form

I wish GM would let us know if the 6.2L is going into the 2010 2500HDs or not. I'm holding off on trading for a custom order 09 GMC 2500HD w/6.0L until I know what the lineup is for MY2010. As I said previously, 360/373 is plenty but I'd be pissed if three months later people are paying the same to roll around with 403/415. It's not just extra speed, the 30lb/ft would be handy hauling up GrapeVine.

I like my 340/450 (8.1)

Thank Uncle Sam for killing the 8.1, large bores are not conducive to low emissions, large bores tend not to burn all the fuel at lower rpm's

When my 8.1 dies I'll probably just get a new engine for it as I REALLY HATE truck pmts.

Speaking of the new 6.0, does anyone know the difference between the tuning on the dually 6.0 and the SRW 6.0?

My 2009 dually is rated at 322 hp, as opposed to 360 hp in the under 10k GVWR set up.

Anyone played with the tuning yet?

If your talking about the 6 speed like in the new Denali's with the 6.2....You can keep it.

All of my 6.0/4 speeds ran perfectly. I got the Denali for the wife and I can't tell how much I hate the way it runs. The tranny is so confused that even my wife is beginning to hate it. And that says alot.

Either dial it in like an Aliison or go back to a 4 speed. Just my .02

I could be wrong, but I think GM had an update for a shifting issue in the new Hydra-matic 6 speeds.