Home Forums Gear Hunting Trucks and Four-Wheel Drives New Chev or GMC with 5.3 or 6.2

I have started looking at new trucks. Don't seem they offer what I thought I wanted. I wanted the iron block 5.3 with 3.73 gears like my 2005.

Seems if you get a 4WD, you get the aluminum block. If 5.3 they have fuel management which shuts it down to 4cyl. I think you can get 3.73 but no one has them. They have 3.42 for the lowest gearing. Maybe with the 6sp auto this isn't an issue.

Questions. Is there any problem with the fuel management system?

What kind of mileage is anyone getting from the 6.2 on the highway. The 6.2 with 3.73 should be a powerhouse.

Thanks

I have a 2010 silverado with the MAXX trailering package which has the 6.2 with 3.73 gears and 6 speed tranny. I can get 18 on the highway if i baby it but usually it's about 16.5. It definitly has more than enough power. I pull a 30' camper and i can set the cruise on 60 and it never goes over 3000 RPM unless it's a really steep hill and i live in very hilly country. My dad has the 5.3 and 3.42 gears with a six speed and i can tell a big difference when i drive his after driving mine, but he has a 32' camper that he pulls with it and never has any trouble pulling it. I think the 6 speed tranny has made a big difference over the 4 speed. Once you test drive a 6.2 you will want it as soon as you start it up, mine sounds awesome.

Jason, is the 6.2 a big block motor or the small block like the 5.3 with modifications? I see they still have the 6.0L in the HD line of trucks also.

Jason, I assume the mileage you list is unloaded and not pulling the trailer? Do you know what your dads gets unloaded?

Sounds like you like yours.

I have a 2007 Avelanche with the 5.3 and the fuel management system. It has about 26,000 miles on it now, 3.42 gears, 4 speed auto. Mileage of a tick over 20 is common on the highway, even at speeds of 70-75 mph. Local driving which is mostly rural with a fair amount of hills is about 17. You have to be light on the throttle to achieve those numbers.

The fuel management system on mine works flawless, you never know when it is 4 or 8 cylinder mode without looking at the dislay. I have heard some say they can tell the transition, but not on mine.

No experience at all on the new 6.2. I did have a 6.0 back in 99 before I bought the duramax. I was HARD pressed to EVER get over 16 with that, about 12-13 in the rural driving I described above.

Hope this helps!

The 6.0 is a gas hog from what i hear. I think my dad gets about 18. He is thinking of tradeing his in for a 6.2 because of the little difference in fuel mileage. I get about 9 or 10 pulling my camper and my dad gets the same pulling his. I had an 06 with the 5.3 before my 6.2 and it got 20mpg too. I never know if mine is running on 8 or 4 cylinders, you never feel the transition. The 6.2 is a small block motor.

I have a 2010 GMC Sierra with the 4.8L V8 4wd, 3.42 gears and 4 spd auto and if you're running 70MPH on the interstate, it won't go up a hill. You have to push the gas pedal down so it will downshift to maintain speed. I'm not towing anything either. It's just geared too tall. The motor makes great power, but it's all over 3,000 RPM, and it's only turning around 1700 RPM at 70MPH.

My 2004 Silverado 4wd has the 4.8L, 3.73 gears and the 5sp manual and it chugs up hills with no problem. It's got 113,000 miles on it also.

I have a 2500 Hd 2010 crew cab with the 6.0l .. its a gas hog i get according to the trip computer 14.0 on the highway.. I have 11,000 miles on truck... plenty of power thou for a gasser...

My pals 6.0, 3.37 gears gets 12-13 in town & 7-8 when pulling a 22' trailer.
It drinks gas like its free.
My 2007 CC 4x4, 4.8 motor, alum block, 3.73 gears gets 16-17 in town and I have hit 22 hwy, averages 19 though freeway.
Most newer vehicles will have the aluminum block for weight savings from what I have looked at.
The new 3.42 gears are there for milage only, and the worse gears for any truck thats pulling or working.
I do not like the FMS, owners I know at work hate them even though they have those trucks, worthless till you hit 60-70 on the hwy according to them, just what they have told me.

I've got the aluminum blocked 5.3 in my '07 Tahoe. It also has the active fuel management.

The AFM is seamless. You literally can't tell when it drops to 4 cyl. Just turned 80,000 and its been absolutely bulletproof (knock on wood).

Lifetime fuel mileage is about 15.7

There are very few times it will actually run on 4cyl though. The slightest throttle input or incline and its running on 8cyl.

Real world,the AFM doesn't do much.

Forgot to add,my Tahoe has 4.10 gearing.

Since you're buying new, instead of buying Govt Motors, why not a new Ford with the 6.2?

Slip, I know what you saying, but I find it hard to change from the GM. GM closed down a small dealership in our hometown like so many others. I don't understand why, except to eventually be able to more evenly set pricing to the public. Seems to me if a small dealer was paying their dues and selling any units at all, it would have been a plus for GM. Might have to at least look at Ford.

I'm not sure if it is the same. but I drive a 09 Avalanche - which is the same set up as you described.

Because of the new 6 speed automatic transmission, the deepest gears you can get is only the 3:42 ratio.

Again, I am not for sure - but I believe that the block is cast iron, only the heads are aluminum.
Anywho - the all aluminum block - which is the same one that is in my Pontiac Grand Prix GXP = is a very good piece - even better then the cast iron block that was in my 02

Absolutely no problems and the Pontiac was a 303 HP option in 2005 in the Pontiac.

The only problem I have with the 5.3 is the fly by wire, where you do not have a cable that physically connects the gas pedal to the throttle. There is a slight lag between the time you press the accelerator and the time it actually reacts to the input and tells the engine to go.

The 8 cylinder runs when you are going up hill or on the flat and level - while you demand it to accelerate.
The 4 cylinder kicks in when you are going down hill and when you take your foot off the accelerator.
Unless you press the button on the vehicle information center - you would never know which mode it is running in.
It also calculates gas mileage in real time.

I'm getting about 16 MPG around town and about 17 - 18 on a trip with no load.

Add a 7,000 racecar trailer and the gas mileage immediately goes down to about 4 MPG. You have to use the tow / haul mode and it keeps the transmission in a lower gear, longer - which makes the truck get crappy mileage.

No problems with the fuel management system, but you will loose approximately 25% of your fuel mileage when you use E-85 fuel.

This is with 20 inch wheels and fully loaded.

The four wheel drive has worked well, except I don't like having to shut off the traction control to go four wheeling.
No truck should have traction control!

Ground clearance really stinks.
I already tore one front spoiler off in 5000 miles.

Once General Motors got its feet back on the ground, they offered something like 40% of their previous dealers the opportunity to go back in business and many opted out - after the crappy treatment that they got when they were forced to sell all their inventory and go out of business.