what are u guys with 6-speeds with 4:10 gears doin MPG wise?? my overhead has stayed at 18.8 for awhile now... truck has 65K on it... is anyone getting better? what about have the computer reflashed at the dealer? i know on my old ford it would help things out to have it flashed sometimes, but some guys got worse milege.. has anyone done this on there cummins?

 

some newby on this forum had said that the 410 ratio wasnt available with the 6 spd. you sure you dont have 373's? what rpm are you running at exactly 60mph? that will tell me all I need to know.

 

4.10s were available with the older NV5600 six speed used up to mid-2005.
4.10s are NOT available with the newer G56 six speed.

The gearing of the newer tranny is shorter, so the new trans with 3.73s is mostly the same as the older trans with 4.10s.

18.8 for 4.10s is OUTSTANDING, if that is in fact what you have. Lots of guys with the 3.73 aren't getting that.

4.10s are capable of really good mileage, actually. You just have to drive 50mph to get it

 

I can probably count on one hand how many tanks of fuel I've used without our 5th wheel in tow, so take my results with a grain of salt. I've seen 17 MPG (hand calculated) running 75 MPH (2500 RPM) on I-10 between San Antonio and Houston. (I know - 2nd generation.)

Rusty

 

yea, its got 4:10's in it forsure, even says on the window sticker as an option. 03-04.5 trucks could be gotten with them.. i've thought about gettin 3:73 gears put in my truck, but i dont know if it would be worth it cause it cost alot to switch out front & rear.

 

Going to 3.73's (or any other gear ratio for that matter) is expensive. I heard about $1,500.00 total. I'll stay with 4.10's. I get high teens, low 20's on mine. This weekend I'll be driving to AZ. I bet I get about 17 because of all the fast highway driving. 2100rpm at 65mph

 

I have he 4:10 rear end and I get 15mpg hand cal 17 by overhead.

 

Nice ride, stock03

The block in my '65 GTO is from a '68 Bird...

 

Now my truck is a 2nd gen, so that probly makes some difference, but unloaded, I can get 24-25 MPG regularly.

 

Fill out your signature so we can see what kind of truck you have. A rokktech crank sensor will give you .5 MPG to 1 MPG and that is on an 03 to 04.5 for sure. Don't know about the 05 model. 06 trucks don't do as well with it.

 

This seems opposite.

advancing the start of injection should help the 325/610 equipped trucks because of the emissions standards forcing Cummins to retard the timing for improved emissions.

So the opposite should also hold true that the 305/555 engines already have their start of injection more advanced and therefore would not benefit as much from more advanced timing.

Not saying this is actually true in real life, just a technical observation.

 

Yeah, that's what I was thinking, too.

 

I'm getting upper 18.75 hand calculated with a last few tanks. I also have 35's and drive alot of highway miles. That MPG is if I keep it between 2000 and 2100 RPM's on the interstate.

 

I bought mine last Nov. and I got 21.0 thru the winter. As it got hotter and using the AC, got down to 18.5 in the summer. Now that it's cooling off mpg is coming back up. I'm only using AC in the PM now and it's back up to 19.0. My actual mpg is a little better them the puter shows. Craig

 

my truck stock 22-25 mpg hand calculated, stop and go trafic high average tank was 27mpg

currently i average 20-22 mpg in the same driving conditions.
never had the reflash for mialge etc, but the truck will be geeting the latest software soon. ive been useing the gps to verify milage since the tire swap, so i know things are still accurate.