Anyone else getting less than 14mpg? My 4th gen got way better economy. I know it’s a truck and I don’t expect amazing economy, but i do expect to get what I got out of my 4th gen which was 16-17, and also does anyone have a vibration coming from the drivetrain when In 4wd hi or auto?
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Bad fuel mileage 5.7 hemi
- Thread starter Steverup
- Start date
Dontfront82
Well-Known Member
Mine is 12-13 city
15mpg highway
15mpg highway
I am getting what I would consider poor gas mileage as well, but the truck's only at 1300 miles and probably needs a couple more thousand to get much better. I am averaging between 13.5 and 15, but the first week was 9-10 (and I was even more light footed then).
As to the 4WD / 4-Auto concern, I get some slight vibration and whirring noises on turns and light acceleration in 4Auto, which I've written off as normal clutch noise in the transfer case. In 4Hi it is significantly more noticeable, but with actual binding on turns - so the 4Auto does seem to somewhat release tension on turns compared to 4Hi.
As to the 4WD / 4-Auto concern, I get some slight vibration and whirring noises on turns and light acceleration in 4Auto, which I've written off as normal clutch noise in the transfer case. In 4Hi it is significantly more noticeable, but with actual binding on turns - so the 4Auto does seem to somewhat release tension on turns compared to 4Hi.
moosem
Ram Guru
16mpg mixed and I drive fast.
smiles5619
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I noticed when I keep it in Auto 4WD, there is poor fuel mileage. When I put it back into 2WD, I get better numbers. Not sure if you keep it in Auto but doing so still locks the axles and therefore poor fuel economy. I believe it is in the owners manual.
Granite5thgen
Well-Known Member
How does 4 auto lock the axels? I thought if it detected slip it engaged the front wheels, otherwise it's in 2wd. Maybe it's different in these new trucks
Front axle is locked but transfer case is not engaged.... when slip is detected, the transfer case is engaged and power sent to the front axle.
moosem
Ram Guru
I use it quite a bit and I really haven’t noticed a huge difference in MPG.Chris
Active Member
As stated, essentially what happens is that in 2WD the axle is disengaged and the front wheels are only connected to the brakes and tie rods (steering wheel); engine never touches it.
Engaging 4AUTO binds the front wheels to the front axle so the wheels always drag the axle to turn it (and technically slow braking due to physics and related boring terminology to stop that moving axle) though it is still disconnected from the engine and rear wheels due to a disengaged transfer case (located right after the transmission, before the drive shaft to the rear axle). However, with the front axle bound, that transfer case (through a clutch similar to an automatic transmission) can deliver power on demand to the front wheels, and even slip a bit so power is still delivered while they can spin at different rates without binding.
This means that, contrary to popular belief, emergency stopping performance (using only brakes, not engine braking) is slightly decreased in 4Auto, while forward movement and control as well as engine braking is increased at the expense of gas mileage.
Engaging 4AUTO binds the front wheels to the front axle so the wheels always drag the axle to turn it (and technically slow braking due to physics and related boring terminology to stop that moving axle) though it is still disconnected from the engine and rear wheels due to a disengaged transfer case (located right after the transmission, before the drive shaft to the rear axle). However, with the front axle bound, that transfer case (through a clutch similar to an automatic transmission) can deliver power on demand to the front wheels, and even slip a bit so power is still delivered while they can spin at different rates without binding.
This means that, contrary to popular belief, emergency stopping performance (using only brakes, not engine braking) is slightly decreased in 4Auto, while forward movement and control as well as engine braking is increased at the expense of gas mileage.
Reduxalicious
Active Member
I average anywhere from 13 - 16 MPG in 5500 Miles, Hand and Computer,
The 16 is around town freeway's and if I'm on the highway not in a cross wind, The 13 is driving north in a 20 gusting to 40 knot head-wind for 200+ miles at 75MPH.
The 16 is around town freeway's and if I'm on the highway not in a cross wind, The 13 is driving north in a 20 gusting to 40 knot head-wind for 200+ miles at 75MPH.
slimchance
Well-Known Member
we have either snow or ice storms every three days around here this year .... so have used the Auto 4 many times ... after reading threads like this one i began to take special notice of the mpg reading on the dash ... i know it is not the exact mpg but it is relative ... started out with 18.2 mpg drove around on local roads with some stop and go and generally 45 mph ish .. after over 100 miles returned home and the mpg was still at 18.2, so i believe the Auto 4 on my trk does NOT effect the mpg in a significant way
I'm only up to about 750 miles on mine, but I can't even get it to avg 14 with a good mix of highway and town. Hopefully will get better with age and it's been cold here in IA. Plus I've been just running the cheap 87 w/ethanol in it. 89 seems hard to find here so I might try a few tanks of 91 when I get some more miles on it.
dutchman187
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I'm hoping warmer weather helps significantly. I'm also in frozen IA and thus far my best tank is 14.6 in mixed conditions. In pure in town, I'm getting about 10.5. I drive like the old man that I am, so it isn't my right foot. I have a nice 8 hour roadtrip on Saturday that I'm interested in seeing the results from. Btw, in my Fuelly log my best fill ups so far have been with 89, even though that requires ethanol mixing around here.
CnyRver
Active Member
My ‘19 crew bighorn(3.21 gears)with 4K miles averaged about 13-14 mpg with lots of remote starts and idling, plus 4wd and crappy winter gas back home in NY. Just returned on a trip from Florida and was getting 22.5 highway if under 70 mph. 20.5 if over 70. City driving in Florida about 17 mpg. My ‘16 crew 4th gen with 3.92 gears averaged 14-16 in the winter and about 20 hwy.
Adrianp89
Ram Guru
Mileage just starting to get where I expect at 7500 miles.
Billet1500 4x4
Ram Guru
This is not quite true, the front axle is disengaged when in 2wd, but not at the wheels. The axles are splined and rigidly attached to the front hubs in fact the only thing preventing the front hub from separating and the wheel falling off of the truck is the outboard stub shaft of the front CV. The front wheels are always connected to the front axle whether it be in 2wd, 4auto, 4hi or 4lo, when the front wheels turn so do the front axles. The point of engagement is at the center axle disconnect which disconnects the axles from the front diff. Basically your wheels are always taking the axle along for a spin. In theory you could pick up some more efficiency by using locking hubs and disconnecting the wheel from the whole axle assembly at the hub itself the trade off is more circuitry, a larger more complex hub assembly and additional unsprung wheel weight so the trade off in efficiency likely doesn't pencil out.
slimchance
Well-Known Member
well in the olden days when i had manual locking hubs on my 1974 Dodge Power Wagon, 360cdi and 4 speed manual trans ... when i unlocked the hubs there was a significant gain in mpg (8 mpg vs 12 mpg) ... of course people today are too lazy to get out of the truck or plan ahead and lock the hubs, it is MUCH easier to push a button
