I am currently looking at ordering a new 2011 2500 truck with the new 6.7HO. I was curious if anyone has the 3.42 ratio compared to the 3.73 and what people are seeing in the mileage difference between the two different gear ratios?

 

I also just ordered my 2011 Laramie Longhorn,Crewcab,Auto, 4X4,SRW with 3.42, and am also hoping to find the same answer to your question. Also I do not know if mine will have the HO engine,but I sure hope so.It should be at the dealers in 6-8 weeks. Thank you,Bill

 

I personally don't think the mileage difference is huge. I base that on my dads and my trucks (5.9s's but still valid). He has a G56 with a .79OD and I have a NV5600 with a .73OD, we both have 3.73's. His final drive is the same as if I had 4.10's, and we get comperable mileage.

Maybe if you lived at 80 and were empty the 3.42's would be a lot better, but for mixed driving I bet the 3.73s may even do a hair better as you can be in 6th more.

 

depends if you are getting an auto or manual as ratios are different. For manual 3.42's would be fine with stock tires, 3.73 if you want bigger tires and or tow heavy. for an auto, you probably dont want 42's unless you are keeping stock tires and wont tow much or anyhting. can get by with 3.73's but if towing heavy and or running larger tires, many prefer the 4.10's like myself. mileage isnt going to much different between all of them. your primary concern should be getting the right gears for your application, not mpg IMO

 

I agree. The 4.10's and the auto are a sweet combo with that double OD. Really makes me want a double OD manual.

 

Me too.

MikeyB

 

3.42's and Auto here....I openly challenge you to tow heavier than what I do


Just because you have 6 gears, doesn't mean you have to be in 6th all the time. My truck, with 265/70R17's, in 5th gear is "basically" the same as a truck in 6th with 4.10's....and it has no trouble getting moving with the 3.42's.


Personally, unless you're changing tire sizes, the 4.10's are never needed, and 3.73's work awesome for most. I'll never have another diesel without 3.42's if I have the choice!!!

Mileage before deletes and winter was 15-16mpg combined, and 17.5-18.25 highway. Winter and the heavy foot and idling after the deletes killed my mileage...but it should start getting better again after it warms up.

Chris

 

Food for thought. . . My 2006 with the G56 and 3:73 would turn 2000 rpm's at 63 mph. My 2011 with the G56 and 3:73 turns 1800 rpm's at 63. Don't ask my how/why because I don't know but because of this difference, I think the 6.7 with the G56 and 3:73's is the perfect combo.

 

How do you determine which gearset you have?

 

Mine was listed under Optional Equipment on the window sticker. . .

 

My sticker just says limited slip differential.

 

They changed the 6th gear with the 6.7L engine in the G56....

Chris

 

That would explain it. . . Thanks!

I'm sure glad they did because that was my only issue with my 2006.

 

07.4+ G56's have the "AE" ratios, every gear but 5th is higher.

 

let me know how that tranny holds up over time with your "heavy" loads and ratios. Its also not surprising your trailer brake doesnt function well with the weight you pull. I think you and Carl are the only ones with those ratios that claim its a good combo