need advice mpg on my 6.0 2500

Discussion in 'Performance & Fuel' started by hunter541, Nov 23, 2011.

  1. ntbush83

    ntbush83 Epic Member 5+ Years ROTM Winner 1000 Posts

    Yeah if your planning on keeping the truck I'd say 4:10 gears is a must. Also does your truck have the manual shifter option on the shift lever? If so let those rpms climb up a little before you shift and give you better power.
  2. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Wow- what does a Backhoe weigh-14,000 lbs???
    Except to hit maybe 2200 rpms at 70 mph-you can't beat the OEM engineers setup.CAI HEADERS EXHAUST- waste of $$ for F
    I'm surprised it doesn't downshift.You must be turning maybe 1850 at 70 mph in 6th?

    If those tire are pretty aggressive-lugged making plenty of road noise-all that noise takes fuel-the low pressure also takes fuel.
    Still 5 mpg??? When someone towing maybe 16000 lbs gets 4 mpg??You are towing maybe 3500 lbs?
    You have a 40 gallon tank?? Under 200 mile range?
  3. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    the C rated tires DO NOT seem to be right for a 2500 truck, they should be E loads, those tires could be part of the problam, as they are gonna flex more under load that will give you a bigger footprint on the road, creating more resisitence, but still shouldnt be enough to put you at 13mpg on the highway. Also does your truck have a tow/haul selector if so use it. Also i would not even allow the truck to run in 6th gear(if possible) if you can lock it out or manually select to be in 5th or even 4th i would do it. its probably causing the tranny to hunt for gears too much and chewing at your mpg.

    I wouldnt invest in getting the bigger gears, they are only gonna increase your rpms, and the stock ones are just fine.
    Last edited: Dec 16, 2011
  4. likinit2

    likinit2 New Member

    The 3:73 gears in the newer trucks are useless. Look at your tranny ratios and you will see both 5th and 6th are overdrives. With 265's I am just over 2000 rpms at 70 and I get 15-17 at this speed depending on which way the wind blows with a 2008 3500 crew 4x4 srw with 4:10s. I also have a 28ft heavy duty all sports steel enclosed trailer i put 6 sleds in and haul 1300 miles out west and my trip average is always between 8-9 mpg with that trailer my 7.5' wide 27 ft snow trailer I get over 10 when towing if I keep it at 70. 9.5 at 75mph. I have a guy I work with who says that his 2008 2500 crew with 3:73 gears will "hunt" and down shift just going down the highway. He has 245 tires and we live in lower Michigan. We barely have what anyone would call hills!

    As far as lugging goes, my 2008 doesn't have the grunt that the 6.0 in my 2002 motorhome has. However with 6 speeds and an engine that is happy running at high rpms it pulls better than any gasser I have had in the past and does it in a civilized manner...
  5. Marcus A.

    Marcus A. Rockstar

    I have an '03 burb 2500 with 6.0, 3.73 gears and 285/75-r16 load range D tires. The tires being bigger have more load capacity at 3305 lb single vs stock tires at 3045 lb. It also has the 4 speed trans but with a 2000 rpm stall converter. The 6 speed gear ratio is better : 1st, 3.08; 2nd, 2.81; 3rd 1.41; 4th 1.0; 5th .76; 6th .67. The 4 speed is as follows 1st 2.48; 2nd 1.48; 3rd 1.0; 4th .75. I tow a 5500 lb camper at 60 mph in 3rd on the highway. OD is too high with the 285/75 tires. Just towed a trailer loaded with wood (est. 2500 lb trailer, 4000lb wood) and it was all in the Pennsylvania country. I only used 3rd gear. Going to stock size tires next time. The tall 1st gear makes it hard to start off and the rest of the gears are too far apart for making towing efficient.
  6. Sierraowner5.3

    Sierraowner5.3 Epic Member 5+ Years 1000 Posts

    i had most of 6000lbs behind my truck with a flat front 6x12 uhaul. i still managed 11 ish on a 13 mile trip. with hills.

    same truck and info as in sig.

    i wonder if its a fluid issue. my old neighbor had a 01 2500 with the 6.0. got like 7 mpg empty or loaded. turned out that some idiot had put 80-90 gear lube in the rear end instead of the standard gm stuff, swapped the fluid out and he picked up 3 mpg.

  7. 2wheelmudder

    2wheelmudder Rockstar 100 Posts

    My 2000 6.0 is running 11mpg empty with 285/75/16 and 3.73 gears id expect a little more, might be the wear? 280,000 miles and some change? towing 10,000# it gets 9 id expect a little better empty like 13 i drive 80% highway or country road
  8. Marcus A.

    Marcus A. Rockstar

    I get 10-11 empty, all short trips on mostly back roads with lots of hills. Can squeeze out 13-14 highway. Towing 5000lb camper is 8-9 mpg. I have a 2000 rpm stall converter that hurts the milage.
  9. Marcus A.

    Marcus A. Rockstar

    Your 265 tires will cause the 3.73 gears to act like 3.60 gears, not helping. I Just drove to Texas from PA in my '03 burb 2500, 6.0l, 3.73 gear, 285/75r16 D range tires. Got 14mpg at around 65. Noticed any thing over 2000 rpm made mpg drop up to 3-4. Not worth it in my opinion. 55-60 mph seems best with these engines.

Share This Page

Newest Gallery Photos