Want to increase towing power?

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LSD stands for limited slip differential, sorta like GM's posi rear. While helpful for traction on dry and somewhat slippy roads, it can cause fishtailing on wet roads in turns until you get used to it.

gears
Without question. Your 4WD is not going to work very well if both axles are always trying to turn the wheels at different speeds.

In the city, it may actually improve but on the highway without towing, it is going to drop. The amount really depends on how fast you like to drive.

No, because it will always be running faster and have more torque due to the lower gearing.

The easy answer to that is to lose the K&N. You will find that it really isn't doing all that much for you.
Sorry I ask so many

That is the reason for these groups.
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Actually T-Bone,although I have limited mechanical skills, I did try sky diving and liked it very much. It can be very expensive though! Thanks Howard

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"TBone" wrote:

THis is a great misconseption. People tend to operate that big 4x4SUV need tall gears for good gas mileage. It dependend on engine type and its power curve and size and truck type and configuration as to the best gearing. A oil burner that reaches peak VE at a very low RPM will do better with taller gears (to a point) than a small gas engine will (and yes the 5.7 Hemi is a small engine with little low speed torque) A big gass engine with a lower RPM power a torque peak might do better MPG wise too (again to a point) but a engine that does not see its torque peak until 4000 RPM and its power peak beyond 5000rpm will not do better with tall gears in a SUV in the real world. Optimum overall MPG with the truck in question will be between 4.10 and 4.56 with OD in use (with OD a 4.10 will be about a 3 to 1 and a 4.56 will be about a 3.36 effect ratio wise) which is better for a truck that size, especailly the later with 32 inch tires. The logic that applies to a streamlined car in drive ratios does not apply to a truck
"TBone" wrote:

A K&Ns (like dual exhausts) is more a state on mind on a modern well tuned engine through design as people look for magic bullets to cure their tall geared whoas with engine not matched to needs. It is a well known fact too the K&N filter gain flow but not filtering out the smallest of particles so media is less restrictive to flow.
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"Hp" wrote:

Even a 3.92 is not likely to be enough for you needs (nor a 4.10) You have a few problems here. The biggest one is the engine itself which is GREATLY over rated for truck duty. The HP ratings look inpressive on paper but most towing and trucking is done below 3500 RPM where the Hemi is kinda gutless and no intake filte change or exhaust change is going to fix this. Chysler should have modified the cam timing and ports for less peak HP above 4000 RPM and more usable HP and torque at lower RPMs where you need it in a truck. It also lacks displacement which mean torque too. (even the old 360 has more grunt below 3500 RPM in the seat of the pants than the Hemi does) How do you fix this? GEARS!!! Get the engine RPM up under load so that it can make more power because nothing you can do short of super charging is going to make it deliver more low torque at lower RPMs so forget trying that. When you consider gear ratio you must factor tires size and the loads you plan to haul. A 4.10 would be bare minimum here with a 4.56 a better choice if you have some serious towing to do. These ratios are not as high as they sound with 32 inch tires and OD and I doubt the mileage will change much with a 4.56 because the engine will be cruising at a more efficent RPM and with a 4.10 it might even improve a bit when not towing and the 4.56 should improve towing MPG a noticable amount. A engine uses the less amout of fuel per HP hour producted when it is operating near it torque peak (which is also were peek VE occurs) and seen the Hemis is at about 4000 RPM you never realy get there ever in daily driving and going through gear getting moving with a 3.54. With a 4.56 you should be able to tow 8 to 10,000 lbs without too much fuss, even in hilly terrain and still cruise nicely in OD.
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At 5000 lbs you are actually the maximum towing capcity of 4900 lbs unless you have the tow package then max capcity is 8300 lbs.
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5000 lbs. Is that the empty weight or after you have loaded all your stuff into he trailer, eg water, propane, food, beer, clothes, etc. ??

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"Coasty" wrote:

These "rated" towing ratings are not based on any real science because some of them are overly generous. THey do not factor in wind drag (because a 8k low profile load on a flat bed will tow easier that a 6k high profile travel trailer) and whether ground is hilly or flat is a factor too Also if a vehicial can tow 5k well, 6k will not break the bank. Personally I do not care what any factory tow guide says because a hemi in a big SUV with 32 inch tires and a 3.54 axle ratio will have a tuff time with a 5k travel trailer especaily if there is hills. Tires have gotten bigger and trucks heavier but axle ratios have generally stayed the same. To me a good tow vehical for the weight being towed can tow the load up just about any hill on you will see on the interstate without downshifting below drive and not have to be floorboarded either. If you are reaching for the floor and/or second gear a lot you have exceeded your capacity. WHen you gear axle lower/deeper it does two things, it increases the amount of wheel torque put down to ground in any selected gear and it allows the engine to crank up a little more and to be closer to its torque peak when climbing a hill in drive at speed which gives you maximum pulling power.
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Hp wrote:

I have a 04 Durango Hemi and pull about 5,000lbs loaded. It pulls it with ease. Up steep hills I drop it to 2nd and tow up them at about 45mph. To me thats pretty darn good up very steep grades.
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miles wrote:

I've got an 04 Durango Hemi also, 2WD, 5 speed auto. With the tow/haul engaged should it be shifting into fifth gear? The manual says it will stay out of overdrive but is OD different than fifth? I tried using the cruise control while towing, at seventy mph it wouldn't stay in any gear longer than a few seconds (kept shifting up/down). I'm probably towing close to 6000 lbs., mostly tow on level terrain to slightly rolling. I'd like to be able to control the shift points, maybe keep it out of fifth altogether. Thanks, B A R
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B A R wrote:

When in tow/haul mode it locks out 5th gear. I believe 4th is still OD and 3rd is 1:1. On flat terrain mine will sometimes shift to 4th but often stays in 3rd. It does not shift back and forth. 4th can pull my trailer at 65mph. Any slower and it's bogged down and struggles. It really needs to stay in 3rd when towing unless very flat and over 60mph. Up steep hills it will shift back and forth between 3rd and 2nd so I manually shift to 2nd on the steep grades.
There have been some transmission programming changes so you might check with your dealer as to what you already have.
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"miles" wrote:

I
The reason it easily bogs is because it is geared to tall for load. I can remember some family sedan in the 60s and early 70s that had more towing power than some of these new "trucks". I get and have trucks for towing power not a "car" in a trucks clothing with tall gears. Reprogramming the tranny will not "fix" anything because it is the torque load on it relative to effective gear ratios to control/develop proper towing power for the load in question. There is nothing more imbarassing than have a big fancy SUV that is marginal towing when taking the time to properly regear for the load it can make it into a very nice towing platform. And the funny part about this is that 20 to 30 years ago we had to use 4.10 and 4.56 gears with 29 or 30 inch tires too for really big trailers, we did not have a OD to mitigate it when cruising and now today people think they need a 3.54 or a 3.73 AND OD with 32 inch tires and wonder why the towing is lacking. If I was going to tow any serious weight with a Hemi (which really is a poor tow engine because of it power curve) in a SUV like a CC truck, I would have 4.56 gear put in and and be done with it. This would yeild about 3100 RPM in drive at 65 for pretty good power on a steep hill (closer to engine power band) and 2300 RPM or so in OD for flat land towing or not towing at all. It would "play" pretty will with that engine power curve and give you a SUV that actually can get out of its own way with or without a trailer in tow. Least not forget to the HP is basically torque x RPM and that at 3100RPM on a hill or 2300 in OD you will have a LOT more HP availble at the wheels than you will at 2700 and 1900 with 3.92s and will not even comment on the what 3.54s are like because it shoud have never been it truck to begin with as it should have shipped with at least 3.92s as standard because 3.54 are a joke in that setup and vehical with that engine.
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