Ok, I have been a loyal HEMI supporter. Bought my first one in 04 and now have an 07. For a truck with 345HP it just doesn't seem to have the umph I expect from a truck with this much power. I bought a standard 16 ft dual axle flatbed trailer to haul around a couple of full size ATV's. You would think I was trying to haul a bull dozer around. First off the back end sags about 4 inches or so. Obviously need some spring helpers or air bags. Gas mileage is horrible, About 9 miles to the gallon on the highway. This is NOT a heavy load [(MAYBE 4,000 lbs) and thats a BIG maybe], but you would think I was pushing it to its max. I haul them to our hunting lease about 200 miles away. I have borrowed other similar trailers from friends to see if there is a difference. They all seem to be the same. Now I realize 4,000 lbs is exactly that, 4,000 lbs. But shurely a truck with this much advertised power would haul that with no problem. If towing is just going to be this hard on it I think I might just have do break down and trade it in on 3/4 ton with a Cummins to haul 2 four wheelers with! I hate to do that. I may make 7 or 8 trips a year with that load. I dont need a diesel that often. I love my truck. Unloaded or with a decent load in the bed its awesome, but a trailer seems to be its cryptonite. Are any of you experiencing this. Dodge raves about towing capacity but I just dont see it. Maybe I am expecting too much of my truck? Sigh!?!

I pull a trailer that was 5000 lbs from North Dakota to Alaska and had no problems with my 4x4. I pulled the same trailer from South Carolina to North Dakota with the 04 4x2 that I traded for the 4x4, it was ok the 3.55 grears killed it with 20s on it. My 4x4 has 3.92 which seems to to much better.

I forgot to add I was getting 14 MPG with both!

i too was a bit disapointed with the squat of my Hemi with a load on it, i was hauling approx 6000 pounds and thought the power was decent but it seems like it's suspension leaves a bit to be desired. when i get the extra cash i plan on a set of helper bags for towing.

EDIT-almost forgot, i was getting 9MPG also.

i tow a 16 ft tandom axle trailer "5000 pounds" daily in the summer with some equipment on it over a mountain 150 miles one way. i can set the cruise at 65 mph at the bottom of the mountain and running about 68 to 70 mph when i reach the top. i am not sure on mpg but i can fill it up in the morning and about half a tank of gas when i get back home. i seam to have alot of power doing this. i have no bitches about the performance of my hemi."2007 hemi reg. cab long box" hope this helps.

Wow 14 MPG! Thats amazing! I might get that unloaded, drafting an 18 wheeler and catching a tail wind. I average unloaded 11 MPG and thats babying it. On the highway I might get 13-14 unloaded. I have the 3.92 gears. Now dont get me wrong here, the truck does have power. I'm not argueing that. It just seems like you have to floor it to get it. My route is through the Texas Hill Country. Decent little rolling hills but nothing major. Average speed is probably 65. It just seems that I have to be all the way in it before that power is what I call "working efficiently." If I had to put my finger on it I would say its a low rpm and transmission combo. Like I said maybe I just expected too much out of it. I was looking for the most powerful half-ton four wheel drive I could buy. And when you look at all the specs of the truck you just expect to be WOWED and I'm just not. Don't get me wrong, I LOVE the truck, I just think it could tow better. And as far as MPG, I dont know how you guys do it. I read all these posts about averaging 16-20 mpg and I have never seen that out of this one. It just doesnt happen. I guess my dilemma is have a Tow Truck (heavy duty diesel) for a Daily Driver or a daily driver for a Tow Truck.

are you running in OD, tow/haul, or OD off? mine has done the same trip (llano) a dozen times with 2-3 atvs on a 14" tandom will no issues. Hell, it likes to run between 75-80 with ease, and gets 13-14ish doing it.

I always run it in tow/haul. I know that cuts out 5th gear and will cause some mpg loss. And your right it does like the higher speeds. Thats basically what I was getting at. Its all or nothing. Now my truck does have a Ranch Hand so that will account for a little loss in MPG, and its 4wd. I just figured this would be kind of like the bridge in the gap between 1/2 tons and 3/4 tons. Lots of power and comfort. My main complaint is the lower cruising speed power. Its like there is a large gap in the power between 35 and 70. If you ride around in that range it just seems to lag. Does that make sense? I really am trying not to be a whiner. That has to be about my only complaint about the whole truck. It really is a pleasure to drive and plan on driving till the wheels fall off. I would just like to find a way to improve the small stuff. I do look forward to my trips to Brady in my HEMI Dodge! You know hwat I mean Phil!

i dont think your complaining at all.... i somewhat know what your talking about... i stepped out of a trick 04CTD into this hemi, and feel the same sluggishness between 30-50. not saying the hemi is not capable, but it does take more of a stern driving style to keep the rpms up... it has to do with the transmission gearing down too much. if it would stay in that lower gear for a little longer, that sluggishness in acceleration would diminish. using Tow/haul was the trick for me, as it will not allow the next gear until it is flat and level and i am maintaining a certain speed... sometimes i wish it would actually change a little faster when in tow/haul. you are not the 1st one to complain about the 07's having odd tranny parameters though. it sounds like they may have altered the shifting sequences between the 06's and 07's.

you may try to reset the pcm/tcm just prior to your next trip. see if it responds differently.

i am missing my trips to llano this year... a new will do that ya know.

Unloaded I am getting 20-22 MPG running 60-65 MPH (Alaska really has no real Interstate). The 14 MPG was in the winter when I moved to Alaska. I was doing 55-65 MPH most of the way through Canada. I do better with my 07 than I did with my 04 4x2....

Like I said, thats just awesome on the MPG. I have never experienced that kind of mileage. I get maybe 14 on the flatest stretch if I'm lucky. But like I said in another post many moons ago I didnt buy the truck to get good gas milage. Just thought it would be getting better than it is. I wonder if a programmer can change shift parameters and still utilize all the gears? Basically improve on the factory tow/haul set up. Like you said Phil, the power is there, but the gearing, rpm range and shifts points could be better. But I can understand that they do have to build the truck to accomodate all driving styles, and I think they may have given up some of the towing capability for the guys that will never place more than a sack of dog food in the bed of their truck.

Superchips was the way for me, I was towing a 8000lb travel trailer with mine, 3.55 gears and its a bit to get moving and big hills were a bit of an issue, but kick it down and pull on through, 9mpg with that 28' windsail behind me. Now pulling a 29' 5th wheel that weighs 6500lbs and night and day difference. My experience Firemands4x4hemi is that if a trailer has alot of tongue weight it will pull like crap! If you can load your load a bit more to the back, get the truck to squat to level instead of down real bad it will get better mpg and pull better, just weird but it works, I have pulled my beast on an equipment trailer and its a load, trailer dry weight is 2200 and truck is 5000, 11 mpg is normal and its a bit of work but I think 3rd gear is this transmissions demise, Get a sc programmer and you will deff feel the difference, helps by holding the shifts longer and the extra hp really helps!

I think that 3:92 gears would help you a lot. The heaviest thing I have pulled was a skid steer on an all steel flat bed trailer. That was pretty heavy but I didn't have any problems pulling it. My own trailer a car hauler pulls quite easily. I personally shift in and out of tow hauls as I see fit. If I am on level ground I let it go into over drive. when I come to a hill I shift into tow/haul. That helps my gas mileage and hasn't seemed to hurt the truck at all. my truck gets up to 15 mpg around town and I have gotten 18 on the highway.

I have a few questions because it seems a little low to me.
What gear do you have out back? Those tires look somewhat large for highway MPG driving. Are they agressive tread? What speed are you towing at? and with the OD off or the Tow/haul on what RPM are you at at that speed on the highway?

Do you have a lift on the truck?
How heavy is that front bumper and does it have a winch in it?
If your back bumper is dropping 4 inches with the trailer on back you need to reload the trailer better. Just because "stuff" fits on the trailer doesn't mean it's evenly loaded right. You might need a bigger trailer to get the weight over the trailer axle where it belongs, not on the tongue. With the nose of the truck in the air even a bit will also hurt MPG. 4 inches is a lot of drop.

Is the trailer a single axle? I am a firm believer in double axle trailers for about everything. They balance the load on their own. I tow a John Deere backhoe on a 20 foot tandem axle with my 1500 and the rear sags hardly at all because the trailer axles are carrying the weight. Real hard to balance 4000 lbs on a single axle trailer.

I know it seems like these are just little things but they can all add up to a couple of MPG easily.

Alot of the seemingly unbelievable MPG numbers you are hearing I would bet are on stock trucks.

This message has been edited. Last edited by: SLAMLLC,

OK I reread some of your posts. 16 foot tandem axle trailer for how many ATV's?
You have a 2 1/2 inch leveling kit. That is going to hurt MPG by letting air under the front. Simply removing the stock plastic air dam under the stock bumper I have heard makes a difference in MPG. You don't have that either and an aftermarket bumper probably weighing 5 times what the stock one weigh's?
Add to that off road tires sticking out of the fenders and aggressive tread causing rolling resistance and further raising the front of the truck. Not to count the added weight of those meats.

Just seems to me every mod you have done was actually detrimental to MPG.