3:21's are good for mileage

[BULLRAM]

I have read in another forum that a member tells everyone that 3:92's will give you better mileage on the highway, that is false it WILL give you better in the city but not on the highway, his conclusion is that the engine is LUGGING at speed (NO) , the engine is fine,
We drove to NASCAR this week end in Dallas, which for me is about 5/6 hours, set the cruise whenever we could ,and A/C on with full gear, wife ,and 2 boys, with there DVD's plugged into the inverter, and we were off, it got 22.8 best at 65 mph, tons of cops riding there, 22.1/ 22.6,were the worst.

[wyat72]

Wow the new hemi really seems to sip the fuel.

[it's all dodge]

Maybe on completly flat land, but with the always getting taller tires of these days, try that around here in these hills, you'd see 2nd gear at highway speeds to make it up them. Or towing that trailer. Even in tow haul with that 545 which puts it in 4th gear you'd be 2.40 gear ratio. I don't know how they would put a 3.21 gear with a trailer tow package, it would constantly downshift. And I take it that is what the computer says for mileage? I bet you do it with a handheld it will come up lower, like mid to high 21s. Still good mileage, guess it all depends where you live, there, Kansas, Illinois maybe, but forget about 3,21s here in Arkansas, Missouri, Colorado, etc.

[BULLRAM]

Good points, let me address them, HILLS???, this is TEXAS, we have a lot, I was constantly going up and down ,with NO downshifting, my 99 Ram with a 318 and 3:55 would downshift on just an over pass, and the computations WERE hand held, not computer , I was stating that the computer was pretty close, no it wasnt in the mountains, just real world everyday driving here, I myself am pretty pleased ,and just wanted to share with other ownwers . I know these are not towing gears, but i only tow a low boy every now and then ,with cub scouts on it in a parade, and 2 jet skis, but nothing major like a lot of people here, and I still marvel on how strong the new HEMI is, I will say it again, in the old days we pulled ANYTHING that would hook up to our 350 Chevy pickup on the bumper and not worry about IF we could pull it or not, and our gears were not that good, and our horsepower wasnt 390 either, LOL :)

[macleoud]

i have the 3.21 and have no problrms with it down shifting alot

[dodgefan360]

With 390 hp and the larger tires, rpms will be lower on the highway for greater mileage. I'd probably get the 3.21 ratio too with the Hemi. I test drove a unit at Arthur Dodge recently with the 3.55 gears and it has balls. For a truck that is. It cruised at 100km/h or 62mph around 1500rpm on the tach which kept noise down and had enough oomph to climb moderate hills (unloaded) without downshifting. Once they upgrade the 5 speed to a true 6 speed automatic, I'll pick one up!

[mirowpl]

i just towed a trailer carring marching band equipment. weight was abpout $3500 on a 16 ft single axle trailer. i got about 14.1 mpg roundtrip. I did not use tow/haul mode. I had 5 other adult men in the truck with me for a total of 6. we were on interstae for about 60 of the 74 miles of the trip. No problems towing no problem passing. I have a 09 crew cab with hemi with the 3.21's.

[dodgefan360]

i just towed a trailer carring marching band equipment. weight was abpout $3500 on a 16 ft single axle trailer. i got about 14.1 mpg roundtrip. I did not use tow/haul mode. I had 5 other adult men in the truck with me for a total of 6. we were on interstae for about 60 of the 74 miles of the trip. No problems towing no problem passing. I have a 09 crew cab with hemi with the 3.21's.

That's great mileage for the weight!

[mirowpl]

interstate helped a lot. did not use cruise as it was in and out too much. drove about 60 mph most of the way as we were traveling with school buses which have a governer set at about 58-60 mph.

[bob1340]

Maybe on completly flat land, but with the always getting taller tires of these days, try that around here in these hills,

I live on pretty flat land, but I am surrounded my mountains. To go anywhere I need to climb from 300 ft to 4500 ft to sea level and up to 4500 again a couple times. I still average close to 20 on these trips and I hardly notice a bunch of down shifting. On my 4.7 '02 model Quad cab with 3.91 I'd usually shut the OD off on the hills. On this '09 Hemi Crew Cab with 3.21 I just let it go on it's own.

[ltdan84]

I drove about 250 miles home last night from Nacogdoches to Austin, and at 60-65, it downshifted alot, but at 75-80 with the RPMs a little higher, no downshifting.
Only got about 19 mpg, but oh well, I'd rather get that going 75 than 22 mpg going 60.

[BULLRAM]

Well 22.8 is not my highest, that is just that day, and 65 with A/C getting 23/24 MPG, for me is a plus, I rather get that.

[soapy]

I just drove 1000 miles from Idaho to San Diego usually driving 80 mph. My ram 4x4 with 3.92 gears averaged 19.2 mpg. I am sure I could bump it up a couple mpg if I drove only 60 to 65 but time is money also.

[BULLRAM]

Well my neighbor has an 09 4x4 and the 3:92's he doesnt get 19 @ 70 /80 so his must be bad.

[Adidas_kn]

Yes the 3.21's are the boss on highway cruises but they absolutely horrible on stop and go up to 50mph driving. I like to shift the gears myself with Range Select and after wringing 1st out to damn near 60mph and 2nd to almost 90 I'd say it's time for me to get some 4.10's and shorter tires. I do 95% stop and go city driving up to 50mph and rarely get on long hauls. I have seen 24.2Mpg at 70mph with me and a buddy in the truck. I'd be happy with improved city mileage and around 20Mpg on the freeway.

BTW I have the horrible 3.21 and open diff combo.

[biggestdiesel]

I just completed a 200 mile trip with heavy throttle and a lot of 70-80 MPH speeds. 2WD Hemi with 3.92s. Averaged 19 MPG and am quite pleased.

[canddmeyer]

I have the 3.92's. While I believe the 3.21's would help mpg some, there is so much untapped power in the Hemi Ram that 3.92's ought to be standard. Reluctantly, Dodge has government mandated mpg minimums to make, so it'll never happen. Dodge could probably put even lower gears in the Ram and it would barely affect the mpg.

I had the bed full of firewood, drove 55mph for 140 miles and got 22mpg. I'm amazed, considering the rating is 18mpg.

[SmokinMirror]

I personally think the Hemis can get much better mileage... My 2001 Ram 4x4/4.10s with the horrid 5.9 Magnum would get 19/20mpg at 55mph... Weird thing was how efficient the 2003 Hemi Rams were, they had the least amount of catalytic converter and mufflers that year. The engine wasn't held back as much either. I knew many customers that averaged 20mpg at 65mph... MDS is not all its cracked up to be, most results are seeing 10 to 15% mileage improvement... I think if the new Hemi was 100% unleashed you would be about to get 30mpg at 55mph.... Just look at the compression ratio differences, my 5.9 is 08.9 to 1 the 09 + 5.7 Hemi is 10.5 to 1 25mpg at 55mph should be a no brainier. Most people need to understand it takes very little power to keep a 5000lbs vehicle moving at 55mph... Its getting to 55 that sucks the gas...

[ltdan84]

I think you may be the only 5.9 Gas driver in history to average 20mpg. I have an '03 with a 5.9 gas and it's gotten 12.5 mpg since I got it. Older dodges with the 5.9 that I've driven or owned were about the same. And mpg at 55 mph is a fairly worthless number too. What is the mpg at 70?

[TwinStick]

My 2000 Dakota w/5.9 360 & 3.92's got 10-12 mpg at best no matter how I drove it, & I bought it new. My Power Wagon gets the same & weighs 7500# with all the gear in it. Go figure.