very poor to aweful fuel mileage when towing

[Shelton90]

I got the max tow package, 3.92 gears, all bolt ons minus a cam; when I pull my 6500 gvwr camper (more than what you’re towing) I get about 10 given wind etc etc etc. You’re doing pretty good boss

 

[RLJ10X]

He's pulling 6400 pounds at 55 mph. That is well within that truck's capability.

You can take all my mods back but one. You take my 4.10 gears, and I'm selling my truck.

 

[Burla]

Tow guide is different from 8 speed transmission and rfe, that is the 20021 tow guide 8 speed. I posted one from the rfe years.

 

[RLJ10X]

^Copy.

Me personally, I wouldn’t have 3.21s; No matter what year, transmission, or engine.

 

[Shelton90]

My cousin has the rfe I have the zf 8 speed. Different tuners but identical mods. The 8 speed is just hands down better in every way, towing, hauling ass, gas mileage, reliability. Well **** y’all know that. Not downing the OP’s rfe, just with the 8 the ratios stay in the torque curve much better and doesn’t fall on its face on shifts. Towing intensifies that feeling of falling in its face

 

[caulk04]

I never knew the 3.21 was available before the 8spd...that'd be awful with the RFE.

My last Jeep Grand had 3.73's with the RFE and ran 31-32" tires. No wonder so many people hate the RFE in Rams.

 

[fulltimerart]

If your trailer has a flat front maybe you could fabricate a "V" nose to help streamline it a little, that might help a little. Art

 

[Lunch]

It about 1/2 the mileage when you tow, maybe a little more. 3.21 with an rfe for the hemi is kinda of a poor set up for towing that heavy. That isn't heavy for a ram, but it is heavy for those gears. I would look up if you are over weight for those gears. I'm not sure it will pay for itself with mileage, but moving to a 4:10 or better might extend the life of your trans, and may help a bit with mileage.

3.21 are not towing gears at bottom 3.73 4.10 should do the job

 

[Masdix Dragon]

Wonder what 373 or 411s will do to gas milage when its not towing?

 

[Ronald Nadeau]

2016 2500 5.7 hemi with 4:10 gears. I get 8-9 mpg pulling my 30 foot camper.

 

[RedSRT4Me]

Wonder what 373 or 411s will do to gas milage when its not towing?

I get 14mpg hand calc on 37's evic shows 15.1
4.56 gears

 

[turkeybird56]

Well, I know no way to compare MY 19 with 75HP 8 speed, but 3:21's, but fer chits and giggles:

Unloaded:

13-18 in Town, 17-22 on Highway.

Towing a 2,200 lb stock trailer, 14', loaded with hay, just over 6,600-7,200 lbs, no wdh, but local towing. I get 10-12.5 mpg.

Above just a comparison as big difference between his 6 speed and the new 8 speeds.

HEMI pull that weight all day, just make sure U schedule Fuel stops a plenty, LOL. If I was towing all the time, I would get a PW or 2500 with the 6.4, or Cummins, all IMHO...

 

[RaptorHD]

You know, I am surprised...everyone wants you to change your rear gears.. There is another way.. Ok, if you have a 4x4 you have NO CHOICE--if your change the rear gears you HAVE TO CHANGE THE FRONT TOO!
So whats a better way to keep your gears?
Get over here and take a look,,,enough said! : https://www.gearvendors.com/trucks-towing.html

They dont have a solution for the RFE, but with enough interest by people they will make it.
I don't talk alot, but when I do I know what I am talking about!

BTW, I love my 68RFE!

 

[crackerjack1957]

I don't thinks so..........no mention of a RFE trans or any 4th gen Ram.......only earlier 2nd gen trucks.

 

[RaptorHD]

Yeah I know,,if enough people show the interest, they will make it.. You could also just do an eaton fuller conversion if you have a 2x4... Just sayin..

I am thinking of converting my 2019 2500HD 6.7 over to a NV5600...

 

[Jerid]

I decided to post in the engine performance forum for my issue. I have a 2011 5.7 ram 1500 with only 44,000 miles. My gearing is 3.21 and its an automatic trans with 4wd. Extended cab. I tow a 24' enclosed car trailer that weighs approx 3300 lbs. the car is a 66 Dart that weighs approx 3100 lbs. ive had the truck for just over 3 years. The truck dodes not seem to struggle when pulling. I have done 4 trips over the 3 years I've owned the truck. Each time my fuel mileage has been 7.5 - 8 mpg. All trips have been mostly highway and no large mountains to climb. I travel at about 55 mph.
The only issue i am aware of with this truck is that when not towing i can feel a slight surge at around 35-45 mph when lightly accelerating.
A few more things, i have set my trk up with air bags so I can keep the truck at the same ride height as it always has and I have made the tongue weight as light as possible. I can not move the car back any farther in the trailer and I am running just over 1000 lbs_---------------------_--------------_------------------

I have a 2021 Ram Limited (new body 5.7 V8) with the tow package and 3.92 gear set. With an empty 14ft trailer, I get 8.5mpg.

When I load two zero turn mowers, weed eaters x2, and a couple gas cans, I drop to 6.2mpg.

Honestly, I love the truck, but am begining to think the sexy mess stops with the body. The engine just doesn't perform the way it was advertised with or with out a trailer.

 

[kurek]

I have the RFE with 3.55 gears, never knew you could get it with 3.21's - what's interesting is on this chart

https://www.ramtruck.ca/en_dir/pdf/ld/LD_TowingDetails.pdf

The top half of the chart does show a combination of 5.7 and 3.21, but the bottom half of the chart doesn't show 3.21 at all. 4th gear on a RFE is 1:1 so with 3.21 gears and 265/70R17 tires the engine RPM at 55mph, 4th gear is about 1900. Pretty sure if I was pulling anything larger than a grilled cheese sandwich behind a 5.7/RFE/3.21 truck I'd just lock out 5th and 6th the whole time.

I haven't seen a BSFC chart for these engines (which will be unique to Ram trucks that have both VVT and intake runner control.. Dodge Hemi cars don't have the runner control I believe - and more restrictive exhaust manifolds due to chassis space) so we can only make a wild guess at the size and shape of the island in that chart.
Most autmotive gasoline engines seem to plateau on BSFC between 1/3 and 2/3 throttle and between 1800 and 3500 rpm so if the Hemi behaves similar you'll get better MPG at 2000 rpm under load than 1400 rpm assuming throttle position is not wildly different.

That example is hypothetical as I haven't seen a chart for these engines as configured for our trucks.

 

[David Langford]

I pull a 30' travel trailer, 7600# loaded. 2017, 50k miles, 5.7, 4x4, 8 speed, 3:92 gears. I live out west so have lots of mountains. Run 9-10 MPG at 65MPH. 20MPG when not towing.

 

[tjfdesmo]

Yeah I know,,if enough people show the interest, they will make it.. You could also just do an eaton fuller conversion if you have a 2x4... Just sayin..

I am thinking of converting my 2019 2500HD 6.7 over to a NV5600...

An Eaton-Fuller in a 1/2 ton? A Roadranger? The transmission alone probably exceeds the payload rating of the truck.

 

[dhay13]

Wonder what 373 or 411s will do to gas milage when its not towing?

in town probably no difference at all and maybe better with steeper gears. Engine doesn't work as hard to get it moving. At highway speeds the 3.21's would likely be better though