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2003+ Chevy 3/4 ton gas trucks

3K views 22 replies 20 participants last post by  inthefield 
#1 ·
What are you guys getting for fuel economy; say empty, light load 3500#, and heavier load 7000#+?

Do all of these trucks come with the 4l80e?

Anything specific to look for on a 100k+ 4wd truck?
 
#2 ·
I'll chime in as my van is pretty light weight when empty and close to (or lighter than) a 4wd 3/4 ton. My 04 g3500 weighs 5500# empty, has 6.0L 4l80e, 3.73s. I get 17mpg empty no trailer. 15 empty trailer, 10-11 towing 7500# (rig+trailer) With the 3.73s mpg varies greatly based on speeds I'm going, hills/mountains, etc..
 
#4 ·
Anything specific to look for on a 100k+ 4wd truck?
I can't speak to the gas engine stuff - but as for general stuff...

Front end components are pretty crappy - stamped sheetmetal upper a-arms, poorly laid out steering linkage, unit bearing hubs with a finite life span. If none of the front components have been replaced figure on $1000 to get it all dialed back in.

With the upper a-arms ,the ball joints wear out, as they are supposed to, but they wear out the a-arm at the same time so you can't get a solid seat with the new ball joint, so you need to replace the whole a-arm. But it is easy enough to repalce the whole thing and with a money you can replace them with higher end stuff just as easily.


If you crank the torsion bars way up they ride terrible. But then you can look cool! :shaking:
 
#5 ·
well mine is not a 2003+ but i have an 01 ex cab longbed with 4.10's and 285's and a 5 speed manual and i get 17 empty and got 11 towing the wifes tahoe on a regular car trailer (estimated at around 8000 pounds combined with trailer) and got 15 with empty trailer. my truck hits the scales at exactly 6500 with me and the wife and a half tank of fuel.
 
#7 ·
I have a 2003 Ex Cab SB 4X4 6.0 with a auto and I get 13-15 mpg down the highway and about 9 mpg towing down the interstate with a jeep on the trailer, I have owned for 6 years and 60,000 miles and have not had to do anything to it except change the oil and one front wheel bearing assembly, the brakes still have lots of pad left with 100k miles on it, The truck has by far been the best vehicle I have ever owned (even thought I dont put alot of miles on it)
 
#10 · (Edited)
06 2500HD 6.0 4L80E 4.10 gears 285's i pull a steady 8-9 around town and 13-14 hwy

with the trailer and truggy loaded up i get around 8.5 doing 70
as far as performance pulling that load.. im not all that impressed with it.. BUT i know this engine has a lot of "locked" power that a good solid tune would make it come alive.. it just feels choked up
 
#12 ·
7 to 8 mpg loaded at 20K lbs + combined weight.

12 to 15 on the highway / city normal driving.

As I've said before TUNE TUNE TUNE. Makes a world of difference.


 
#13 ·
I get around 13-15 MPG empty during the summer, and 11-12 during the winter. This is an '03 2500HD CC/SB 6.0L 4L80E that I bought new and now has over 100k miles on it.

Parts that have been changed:
- shocks - factory versions were trashed at 85k
- front brake caliper, pads front and rear
- oil pump - was fine when I parked it in the evening, the next morning I started it and had no pressure...this was about 100k
- water pump was leaking and replaced at the same time as the oil pump
- driver side power window
- rear door latch mechanism and body control module - kept thinking the rear tire was being opened when it was not, would chime and turn on the lights randomly and sometimes set off the factory alarm in the middle of the night

The oil and water pump are really the only major items.
 
#14 ·
I have a 2003hd 6.0l with the 4l80 and 4x4. The cam position sensor, exhaust manifold gaskets, water pump, and just small maintenance items have been replaced. I get 11-16 unloaded everyday driving with it. I really love it, it came with a 1200lbs utility bed on it and i get 9mpg with that, I took that off a while ago. The snow plow package is kinda a cool option if you can find it, i am wired for strobes, have a bigger alternator, bigger trans cooler, and bigger skid plates. O and towing my Toyota pickup with all my gear including the utility bed weight around 8500lbs guesstimation I got 8.5 mpg pulling over the summit.
 
#18 ·
Snow Plow Prep is same trans cooler as the towing package and skid plates are the same either with the plow package or stand alone option.

Isn't there an issue with the T-case pump rub on these trucks as well? Can't remember the details though. Might want to keep an eye out for that, or plan on fixing it.
That is the autotrac transfer case in the 1/2 tons.
 
#16 ·
I have an 04 Regular Cab 2wd 2500hd with 4.10's and at 70mph it is at 2500 rpms and I am getting almost exactly 14mpg. If the speed is faster the mileage goes down FAST. In town I don't bother checking but when I did it was around 1mpg. On long trips the mpg it gets makes the 34 gallon fuel tank feel like a 10 gallon tank as it GOES FAST. Truck is completely stock with stock tire size and highway tread tires.
 
#17 ·
'04 Avalanche 2500 8.1 with a dyno tune - I get 14 highway empty, 8.5-9.5 towing 7k total on an open trailer through the hills of PA, and got 8.5 towing a light (3.5-4k) 7x16' enclosed trailer last weekend - This is all with the cruise at 5 over, and just letting it eat on the uphills.. If I drove it like I cared, I'm certain I could get more by getting a run down the hills and letting it pull down up the hills.
 
#21 ·
My boss has an 05 6.0 4x4 with 4.10 gears. He runs 265 instead of the original 245 and we get between 7-11 mpg not towing with a small tool box and a lumber rack. Good thing is on long trips you don't have to hold your piss long cause you stop all the time to fill it up. He has maybe 80k on it. I know some emission thing set the check engine light off and it was $800 for the dealer to fix it.
 
#23 ·
My 03 CCSB was dead nuts reliable at 13MPG, it didn't matter what I was doing city, highway, 13-13.3 every tank it was empty. With ~5k worth of boat 10-11. The only issue I had with it was that goddamn steering clunk, I think the dealer had it 3 times, it was good for 10k then it was back again.


Kinda hijacking the thread, but since the attention is here I figure I'll ask.

Looking at two trucks this weekend.

Truck one) 03 ECLB 2wd 8.1L and the 5 speed allison 43K on the odometer.

Truck two) 06 ECLB 2wd 8.1L and the 6 speed allison 61K on the odometer.

Those that have ran em pros and cons of both the transmissons? Is there any difference in reliability?
 
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