dsl21

Hi guys I have a 2004.5 2500 ,4x4 , quad cab ,shorty ,auto ,410 gears, I get 15 to16 averge on fuel milage is this normal my 01 6 speed 4x4 got 20+ what can I do to get better mileage I have 25k miles on this 04.5 is it worth the hassale and money to trade it off on a 305 truck this 600 is just what I want but the mileage sucks

PsRumors

Put 315s on and it will go up some....it's the gearing.

v8440

It's not ONLY the gears. The 305 horse motors lacked some of the injection confuction that the newer ones have. It may be the 3rd event, I don't remember for sure. I do know that everyone across the board seems to report that the 305's just flat get better mileage. Whether it's worth it, only you can decide. That'll probably vary with fuel prices too.

Superduty

Someone needs to remove the 3rd injection event on those 6x0 engines. Hmmm....

Jason Foster

I have a 2005 3500 QC 4X4 6 speed manual with 3.73 gears 265 tires. I average 20.5 mpg at 60 mph. It is not quite broke in with 2600 miles. At 75 mph I avg. about 15.5 mpg. You could have the gear shop install 3.55 or 3.73 to help. Approx. $500.00 per pumpkin. Bigger tires won't help much because they most likely will be wider which will increase rolling friction as well as lift your truck up higher increasing wind resistance. I would say change gears and keep the truck you have.

rich

I got about 1.5 to 2.5 mpg more when i put a power box on it. I get anywhere from 19 to 21 w/o trailer and 9.5 to 14 with trailer

Hayseed

Work the motor and the mileage will go up Load it!

04ctd

diesel service power kleen
$12 at wally wordl

~2mpg

4:10 gears, was 15mpg, pushing 16.9 now.

K&N FIPK and strait pipe, no gain,
just noisy and annoying after 2 years.

longbed

I have an 03 auto i only get 16 average. But i do start and stop driving . If im just on the highway i probably get 20 mpg. I am also looking for ways to conserve.

dsl21

Has anyone heard of a reflash for the 600s I heard somethin about ot on tdr who has tried it does it help also is it good to switch the gears or switch the whole axle to get higher gear ratio I am going to a 315 tire what should my speed be at 2k rpm I am doin about 66 now what would it be if I went with 3.73 gears also has anyone tried piers camshaft he said it gained him 3 mile to the gal on his 600 thanks guys

rockhound

you are getting about as good as you are going to with the 4.10 gears

i have three buds with the same truck as you with the 4.10s and my 05 dually with the 3.73s gets consistantly 1.5 to 2 mpg more than they do whether we are towing or running empty

i get around 17.5 to 18 mpg and run from denver to over 8500 ft every night about 35 miles of good hill climbing

the larger tires actually might help. dont go too much larger but if you could lower your rpms by 50-75 at 65 mph you could see some improvement. at 70 mph my 3.73s are running at 1950 rpms and don't crack over 2000 until i reach 75 mph

Tortured

Thats what my RPM's are, about 1950 at 70mph. I've been reading posts where guys with 6 speeds are claiming 2200rpm doing 60mph. If that's the case I'm glad I have an auto.

dsl21

so if I went to 3.73 gears I should pick up about 2 miles agallan?

MikeyB

Increase the timing. Use the Rokktech modified crankshaft sensor or modify the tone wheel. Do a search in the 3rd gen Perfomance section for the timing mod.

MikeyB

Rusty69

I just got back from a 600 mile trip. My 04 got 19.3 MPG running 80 to 85 mph with no load.