2500 can’t pull a trailer

[Pnied919]

I have an 04 2500 with the 5.7 and I tried to pull a 12’ trailer and I had to down shift to 3rd to stay above 40 going up hills. I have replaced plugs and coil packs 12k miles ago and 1 O2 sensor and map sensor within the past 1k and just replaced the tb without anything changing and help would be appreciated.

 

[tron67j]

What is the loaded weight of the trailer, and the loaded weight of your truck? Do you have engine mods, really big tires, or other accessories that can impact performance? Has this been a long term problem or just recently started? Does your manual call for 89 octane and if so, have you run tank to empty before filling with that octane? Does your engine knock going up the hills? If this just started, perhaps you have water in tank, run it to almost empty, then fill with 89 (premium not needed) and see what that does. The above will help eliminate some simple things and let others here start to think more about it. Good luck.

 

[392DevilDog]

Downshifting to 3rd for hills sounds perfectly fine to me. I run my 15 6.4l in 3rd gear when in the hills.

The Hemi needs RPM to make power and 3rd gear gives it RPM

 

[jawzs2]

How does it run not puling the trailer, as asked above, were all those parts replaced to address this specific issue or something else? Does the trailer have brakes, are they adjusted correctly?

 

[392DevilDog]

I own all 3 of the big gas engines by Mopar.

8.0l V10
5.7l Hemi
6.4l Hemi

And all 3 like to be in 3rd gear when towing hills.

The 2 Hemis have 3.73 gears and the Magnum has 3.55.

3rd gear gets them near peak power.

 

[Pnied919]

Maybe a 2000lbs trailer and everything is stock on it and I have tried 87-93 octane fuel in it and nothing changes. I have tried copper plugs too and no difference. it does have a couple small exhaust leaks and it’s cut off after the muffler honestly I just want to get more then 11mpg empty and be able to drive without having to downshift every hill

 

[CheechDogg.0n37s]

That is normal behaviour for a 5 speed .... think about the 8 speeds now, towing you are going to have them drop to 6th and sometimes even 5th going up hill .... everything sounds good

 

[392DevilDog]

11 mpg and downshifting is what you will get with a 2500 and a 5.7 Hemi.

 

[CheechDogg.0n37s]

Maybe a 2000lbs trailer and everything is stock on it and I have tried 87-93 octane fuel in it and nothing changes. I have tried copper plugs too and no difference. it does have a couple small exhaust leaks and it’s cut off after the muffler honestly I just want to get more then 11mpg empty and be able to drive without having to downshift every hill

Not going to happen with a 5 speed especially if you are towing .... you probably have the 3.73 and not the 4.10 gears correct? ... regardless which ones you have you are not going to stay in 5th gear going up a hill towing ever ...

 

[392DevilDog]

The Hemi makes its power over 4000 RPM. So at 40...even 2nd keeps it away from 4k.

And 11 Mpg is pretty good with a HeftyDuty and nearly 400 HP motor

 

[CheechDogg.0n37s]

View attachment 484711View attachment 484712

The Hemi makes its power over 4000 RPM. So at 40...even 2nd keeps it away from 4k.

And 11 Mpg is pretty good with a HeftyDuty and nearly 400 HP motor

Yeep !!! No need to worry .... don't force it when towing either, let it do what it wants to do ... if you don't you are going to end up cooking the tranny

 

[Pnied919]

There any way to give it more power so it’s easier on it? I feel like I’m beating on it just to go from point a to point b. And is it normal to have a power band feeling at 2500 rpm?

 

[392DevilDog]

What did you drive before this truck?

I am a bit confused by what you are asking.

What is it you think it isnt doing?

What do you want it to do?

A 2500 weighs much more than a 1500. Therefore it takes more power just to move it empty.

5th is over drive. You really never want to be in it while towing anyways. 3rd is the first gear to offer the engine help. Honestly...i drive mine in 2nd from time to time just to feel the power.

Not sure what you mean by beating on it. Being in 1st 2nd or 3rd is not beating on it.

Trying to stay in 5th or 4th is lugging it and is worse overall for the engine and transmission.

 

[Smokeybear01]

I used a truck with the 5.7 for work for a couple of years towing a small trailer with 2 quads on it and it literally screamed up hills. Passengers would grab the chicken bar and look at me like I was trying to blow the engine up. I'd just look back at them and say, "You get used to it."

 

[tron67j]

All good response above. I had 2003 2500 (parents have it now) with 5.7 and I think 3.73 gears. Flat towing ran fairly even at too gear but hills do get the hemi working at a higher gear. If you find another similar engine unit, take it for a test drive with load and see if it is similar. I was at 9-11 MPG with travel trailer average from Upstate NY to Florida. Just the way it goes. But still recommend getting tank almost empty and run a couple tanks with detergent 89. Exhaust leaks can impact fuel to air ratio, which impacts efficiency and MPG. Should have that fixed to at least eliminate one factor impacting economy.

 

[CheechDogg.0n37s]

There any way to give it more power so it’s easier on it? I feel like I’m beating on it just to go from point a to point b. And is it normal to have a power band feeling at 2500 rpm?

Regearing will help you out "a bit" but honestly the money spent just to tow might not be worth it ... if you do re gear you would be looking at 4.10s but the money to do so just for that little gain too me wouldn't be worth it ...

Now if you decided to put some 35s on it "I" would put some 4.56s on it and then you would really feel the difference ...

 

[Theck4291]

I own all 3 of the big gas engines by Mopar.

8.0l V10View attachment 484706
5.7l HemiView attachment 484707
6.4l HemiView attachment 484708

And all 3 like to be in 3rd gear when towing hills.

The 2 Hemis have 3.73 gears and the Magnum has 3.55.

3rd gear gets them near peak power.

Nice 2nd gen man. looks awesome pulling that trailer.

 

[crash68]

The Hemi makes its power over 4000 RPM

^^^ this
many seem to think horsepower tows a trailer but it's actually torque, need to get the engine rpms to where it's at.
Part of why diesels tow better, the torque is down low and make more of it. The EcoDiesel and CTD torque peak is at 2K or less.

 

[392DevilDog]

Nice 2nd gen man. looks awesome pulling that trailer.

Thanks. Pic if it caught in the wild...lol

 

[zogg]

When I used to tow a trailer I’d pray for 11 mpg….never got close. I’d suggest you truck is doing its job as designed. Only a $10,000 diesel would fix this.