GMC Sierra 1500HD ???

[Done Working]

Hi Gang
My Safari is getting old and I have been looking for a new TV.  I have been looking for a rear wheel drive 2005 GMC Sierra 1500 with the 5.3 litre. Yesterday I came across a 2005 GMC Sierra 1500HD rear wheel drive, this thing comes with a 6 Litre.
Does someone out there know what am I to expect for gas mileage (real miles) when compared to the 5.3 Sierra.
I really don

[paxsman]

I have a 2005 1500 Silverado 4wd with towing package.  I also have the 4:10 gears in my rear chunk (Not good for gas mileage but great for towing).  I get 16-17 in town and 16-18 on highway.  I have a Jayco 14SO which weighs approximately 3500 pounds.  With the travel trailer I get 12-14 mpg.  I know co workers who have similar vehicles with taller rear ends; they seem to get between 17-18 mpg.  So in short you need to know which rear end you truck comes with to determine the Mpg.  The HD versions typically come with short rear ends to help with towing capacities.  As far as the 5.3 is concerned so far it seems to be a good engine.

[wavery]

It's really all in the math. The bigger the engine, the more efficiently you can carry a heavy load. Rear end gears make a difference when towing a heavy load also.

Only you can answer the question about what % of the miles will be dedicated to towing a heavy load. That's the balancing trick. If you're feeding the bigger engine while 90% of the time it is used for commuting, that choice may not be the best. However, if you use the truck mainly for towing a heavy load, that may be the best choice.

As I see it, the decision boils down to a few things:

1. What is the definition of "heavy load"?

2. What % of mileage will be dedicated to towing?

3. How much "Macho" effect do you desire?

4. What terrain will you be towing in?

A Chevy 1500 PU of any configuration is quite adequate in pulling and stopping almost any PU (all that I can think of).

You will probably sacrifice about 2MPG in the empty vehicle with the bigger engine (all other things being equal). However, when towing a heavy load, you may actually get slightly better mileage when towing in adverse conditions (mountains, wind etc).

My S10 PU with a 4.3V6 and 3.42 gears pulls our 3300# TrailManor, 2 passengers and all our gear just fine, even in the mountains. We only get about 14-16MPG towing. However, we get 24MPG while not towing, so the difference is quite substantial. I just use this as an example because, again, it's all math. When our TV is empty, it is quite light. When we are towing, the % of weight increase is substantial. With the Sierra 1500, you won't be seeing the % of increase that we do.

In short, if you are towing a PU with the Sierra 1500, a 6.0 liter engine is a bit of over-kill and you will pay if you use the vehicle as transportation too. If you are towing a larger rig (6000# +), the 6.0 may well be the better option.

Now...........having said all that.......I've gotta go down and install Air Bag leaf spring helpers on my S10.

[flyfisherman]

It all hinges on that rear axle ratio ...

I have an '02 GMC Sierra, 2 whl drive auto tranny with the small V-8 (4. and with the 3.42 axle ratio. Also have a low profile fiberglass bed cover which helps a tad on the highway gas mileage ~

I have did a 22 mpg highway driving on the xway (not towing of course) at 55 mpg - problem here was everything was flying past me! Doing 70 it will deliver an honest 20 mpg. The good thing about V-8's is the gas mileage towing is not affected as much as with a V-6. On the level can tow the little Starcraft and get 19 to 19 1/2 mpg at 65 mph. Of course the mountains will scale that down to 16 to 17 mpg.


Fly

[brainpause]

To give you a simple answer, your mileage will not be great when not towing. I have the 5.3 and get about 14mpg. If it was mostly highway, I might get 16 or 17mpg.

The 5.3 is an engine that has a lot of miles on it, and a lot of proof. It is a proven, good engine. The 6.0, IIRC, is a newer design, but also is a good engine by my understanding.

The 1500HD will ride a little rougher than the 1500. It is essentially the same as a 2500. Decide if you can put up with that.

Read/lurk around the forums at //www.gm-trucks.com and maybe you'll find specific kudos or gripes about the 6.0.

I did drive both in test driving. I could not appreciate a significant amount of difference in power of the 6.0 above the 5.3. I agree with the rear gear ratio being the clinker. I have the 3.43, and wish I had 3.73 or 4.10, although we get by.

Larry

[GeneF]

In comparison, I had an 02 1500 with the 4.8 and 3.73 gears.  I got aboout 10 to 11 towing.  23b was around 4000 lbs.  16 to 17 not towing.

Now I have a 2500HD with the 6.0 and 4:10.  I get around 8 to 9 mpg towing my tt that is around 8000 lbs.  13 to 14 running around.  Truck tows like there is nothing behind it but it just won't pass a gas station.

A 1500 with the 4.8 and 3.73 gears will pull a pup fine.  But if you are thinking about moving up, the 5.3 may be the better bet.

[Done Working]

Thanks guys,
With your experiences and information, and with the from other web pages, I was able to purchase the new to us 2005 GMC Sierra 1500HD with confidence. This truck only has 56,000km (34797 miles) on it. Drives like a dream. The 6 litre engine purrs like a large kitten.
All equipped and ready to pull.

Photos to come later.

Thanks again.

[austinado16]

Nice purchase! Looking forward to photos.

Just to chime in (late) on the power/gear ratio/mileage equation.  Our '90 Suburban 1/2 ton 4x4 with 5.7L (small block 350) has 3.42's and gets about 17-18 on the highway, and 14-15 towing.  We don't use it as a commuter, so I don't know what it gets "in town."