G56/mileage Question

[Moose]

The time has come for me to look for a different truck... As it turns out I have need of more cab space then my regular cab 06 can provide... I would like to go back to a manual trans but I am a bit leary of the G56 with it . 80 : 1 OD ratio... I am looking for feed back from G56 owners on what kind of mileage you are seeing as well as which mods helped the most... Chances are that I am going to be getting an 05 because I really prefer the interior of the older 3rd gens to the newer ones... I would love to get an NV5600 but those things are impossible to find these days... Any input would be greatly appreciated... TIA



Moose

 

[roperteacher]

Hey there. . I have an 06 Quad cab 3500 SRW. I have 14,000 on the truck as of today. I pull a Living Quarters horse trailer and three horses. Loaded I guess it weighs 13,000 or so. Trailer is 30 foot aluminum and each horse 1200 pounds or so. EMPTY highway I am getting 22-23. Back and forth to work, some hwy, some streets I am seeing 19-20. LOADED highway I am getting 13-14. Yes thw G56 is low geared but I usually drive about 65 or so which is a tad over 2000 RPM. I do not have a 4x4... All hand calculated with a little power service/MMO additive.

 

[GButia]

I have a 06 2500 quad cab swb g-56 and am seeing just under 20 on the highway and 17-18 around town on summer #2. Winter fuel 17-18 on the highway and as low as 16 in town when the tank is mostly city miles. I use powerservice additive regularly. . Of the 3 third gens I have owned... the g-56 has gotten the best mileage. (previous trucks... 1 auto 1 nv5600). So I have nothing but good things to say about this transmission so far. Much smoother shifting than the nv5600 to boot.

 

[CDonaldson]

Hey Moose.



First, I am doing most all of my driving at an altitude average of 7-8K ft elevation. I am getting an average of 17-18mpg unloaded and 13-14mpg pulling right at 12,500lbs loaded. The few times I have been below my normal altitude, but at altitudes of 3-5K and run out a full tank, I have been getting 19-19. 5mpg unloaded and 13. 5 to 15mpg pulling the same 12,500lbs.



I am running BFG AT 315-70-17 tires and have a KORE leveling kit. Average speeds are at 65mph in the lower altitudes with flat and straight roads, and 55mph at the higher altitudes in windy mountain roads. I do tend to use 5th gear more often in the mountains. The larger tires keep the rpm's right at 2K to 2200.



I can tell you that I really LOVE the G56 transmission, very nice hauling. I start out in 2nd unloaded. Nice smooth shifting, no problems in 16K miles so far. I get into the old Ford 5-speed ranch truck and truly know why I love the G56 after a day of hauling.



CD

 

[BHaden]

Ditto to all of the above. My mileage is similar to the examples above and, YES, it is a sweet shifting box

 

[RobertP]

unlike above i drive the crap out of my truck and still see at least 17-18 mpgs empty. if i do by chance drive normally i have seen a best of about 21-22 empty, on the highway. my last trip towing about 10,000lbs, i was running about 70 mph for half of the trip and the rest was between 85-90mph i got about 8-9mpgs. i have to say i have been more than satisfied with my G56 trans.

 

[mlewis73]

With 15,500 on my truck, pulling the same types of stuff as Roperteacher, I'm getting the same types of mileage he is.



I LOVE THE G56. No complaints at all about mileage. At 68mph I get much better mileage than at 73-74, so I stick at about 68-70 on the highway... posted speed limit. Gotta stick as close to 2000 rpm as possible to get the good mileage.





Mike

Hey there. . I have an 06 Quad cab 3500 SRW. I have 14,000 on the truck as of today. I pull a Living Quarters horse trailer and three horses. Loaded I guess it weighs 13,000 or so. Trailer is 30 foot aluminum and each horse 1200 pounds or so. EMPTY highway I am getting 22-23. Back and forth to work, some hwy, some streets I am seeing 19-20. LOADED highway I am getting 13-14. Yes thw G56 is low geared but I usually drive about 65 or so which is a tad over 2000 RPM. I do not have a 4x4... All hand calculated with a little power service/MMO additive.

 

[mlewis73]

unlike above i drive the crap out of my truck and still see at least 17-18 mpgs empty. if i do by chance drive normally i have seen a best of about 21-22 empty, on the highway. my last trip towing about 10,000lbs, i was running about 70 mph for half of the trip and the rest was between 85-90mph i got about 8-9mpgs. i have to say i have been more than satisfied with my G56 trans.

Oh, you SPEED DEMON!!! :-laf

 

[AKaiser]

NB. All figures hand calc'd. If you stay off the 4 lanes and out of congestion, you can get close to 23 MPGs with summer fuel. Last tank was in the 22-23 ballpark. I've begun to drive a more direct route to work, which is 1/2 county backroads (all paved, max 45 MPH) and 1/2 uncongested U. S 31 (4 lanes, 60 MPH Spd Lim) and a short stretch thru Franklin, IN, (20m miles south of Indy) and out of most traffic (I go thru Franklin College campus).



I'm curious what it would do with the . 74 versus . 79 OD gear. Beginning to wonder if 3. 42s would make much difference. My next test is to do 65 MPH on the interstate for a solid week to see what that does.

 

[HNelson]

My wrecked 05 NV5600 got replaced with an 06 G56... . I can't tell a difference in mileage. Min-Max-Average seem to be identical between the two trucks.

 

[MRosinski]

Unless you find a nv5600/3. 73 the mileage will be just about identical between nv5600/4. 10 and g56/3. 73

 

[AKaiser]

I would say there shouldn't be much difference on any transmission/rear gear combination unless you are (guestimated)



a. pushing the RPMs into the 2200 and up range,



and/or



b. pushing the MPHs above 70, therefore pushing major air.



I use these figures, as my truck with stock tires would be 2200 at 70, but I have a 33 inch tire, so it runs about 2100 at 70. I really notice the fuel consumption take a spike at 75 MPH, just a shade over 2200 on my truck. I base my assumption on the way a diesel engine determines fueling, which is load dependent, not speed dependent. That includes engine and powertrain losses that require additional load, hence the high RPM fuel increase.

 

[Mrudolph]

I'm hoping my mileage goes up some once the 3. 42 gears I have on order get installed, as all my miles are at interstate speeds.

 

[SSwords]

I get 20 to 22 mpg on the interstates I try to stay about 70 mph give or take 5 towing a 32ft fith wheel with slider 13 to 10. I do have to say I like this trans alot better than my 03 auto 48re and my freinds 03 nv5600 just shifts so nice

 

[DHuffman]

For '07 the G56 received a 0. 742 OD (not on all 5. 9L equipped trucks?). Mine has the new gear, and my RPMs @ 65 mph are 1975.



In mixed driving, I am averaging close to 18 mpg (truck has 6,000 miles on it).

I love this engine/transmission combo.



Later

 

[AKaiser]

For '07 the G56 received a 0. 742 OD (not on all 5. 9L equipped trucks?). Mine has the new gear, and my RPMs @ 65 mph are 1975.



In mixed driving, I am averaging close to 18 mpg (truck has 6,000 miles on it).

I love this engine/transmission combo.



Later

Must be nice :-laf

 

[TowPro]

I'm hoping my mileage goes up some once the 3. 42 gears I have on order get installed, as all my miles are at interstate speeds.

When you going to get around to this task? Several of us are waiting!



NOTE: run a couple tanks and figure out the MPG with pen and paper before and after the change. I see post about 20mpg; My Overhead display shows +20 all the time, but when I figure it out with paper its around 18



I also hope you make the change during the summer. If you did it in the fall there is a chance winter diesel might come out the same time and mess up the results

 

[ENafziger]

I've got a G56 '06 truck with 34k miles. Overhead has shown as high as 23 mpg, but the best I've every gotten hand calculated has been 18. 2. Overall average for the life of the truck is right at 16. 2 mpg. --Eric

 

[LFalconer]

My 06 3500 DRW G56 is currently getting 17. 36 in mixed, non towing driving.



I haven't run a long hiway, unloaded run yet.



However - I am happy with this, as my 02 Ford 7. 3L with Auto at best gets 15. 2 in same driving and it is a SRW.



Luke

 

[HNelson]

Unless you find a nv5600/3. 73 the mileage will be just about identical between nv5600/4. 10 and g56/3. 73

And my experience shows NV5600/3. 73 is identical to G56/3. 73. Either the engine doesn't care about the difference, the G56 is a more efficient transmission, or the additional time spent in 6th versus 5th makes up for worse consumptions in 6th. I know I use 6th more in town with the G56 than I did with the NV.