Ok guys and gals, I have a question... We have a 2007 1500 Mega Cab with the 5.7 Hemi and it's a tank, and is currently burning WAY WAY WAY more fuel than I am interested in paying for... So, we're looking to do something different with this truck and trade for a vehicle for the wife... Probably a new Grand Caravan, but that's neither here or there...

We own a 2003 Durango 4.7 3.55 towing package 4x4 SLT+ and the Vehicle Tow Ratings Database show the truck at 4400 pounds with the 3.55's and 5700 pounds with the 3.92's... I agree there is some difference between the two ratio's, but where are they finding an extra 1300 pounds in towing capacity by changing ratio's to slightly lower... I mean we're not talking 4.56's here...

I tow a 21' Bass Boat that has an MFR trailered/rigged weight of 4400 pounds (unconfirmed by a scale by the way) and it tows the boat pretty well... Better than my old 5.3 Chevy Avalanche with a 7200 pound rating...

So, to shorten this up, anyone done a gear swap on one of these and if so, what could I expect to pay for it and what kind of hit in mileage can I expect, we're getting 14.4 average now in town...

Thanks in advance...

 

Going to 3:92 gears will I estimate drop your mpg by up to 20 percent. So you may end up around 12 mpg average. going from 3:55 to 3:92 gears will give you a very noticable difference in towing power.

 

It is a very big step between the ratio's. I would install a trans cooler as well to tow that much weight. But I think you would be happy with eather the 3:92 or 4:10.

3:92's should be plenty.

5.3 Chevy Avalanche has what ratio? and why are you trying to compair this to your D?
What, it has a bigger motor, different gears, what about the trans ratios?
Dude these are two completly different animals. You can't compair the two.

 

I understand the Avalanche and Durango are two different beasts... I mentioned that I thought the 4.7 D with the 3.55's did a 'better' job than the Av did...

 

gamble,

I would problaby stick with the 3:55 gears you have as you said that it pulls your 4400 pound boat just fine from saving fuel standpoint.. As you have a tow package, it has a oem tranny cooler but I would do as hydra suggested and that is to upgrade your trans cooler to make sure the tranny stays cool under load.

I would recommend you to at least maybe change your paper air filter with a OEM K&N replacement so at least your 4.7 can breathe better under load.

also, you may want to purchase a tuner/programmer to get some extra power out of your 4.7 from superchips. You may notice better response from your engine when towing and possibly slightly better mpg too. They are the only ones that makes a tuner/programmer for the 4.7 family.

These two upgrades are cheap vs changing out your gear ratios (front/back) and do not physically alter any of your OEM stuff and you can revert back anytime.

 

True.

Ken's right. The tuner, (I would sugest the new Max Tuner from Hypertech) trans cooler, and a drop in K&N air filter would wake the beast up.

Changing gears would cost a lot and you would haveto replace both front and back.

 

Good advice guys, thank you... I figured I would be alright with the 3.55's, but wanted someone elses opinion... And I'll be looking for an aftermarket tranny cooler... I think that's the only reason they want the lower gear, but this thing does tow like an ox for a small 4.7... A CAI and Tuner will also be in the future, since we own this truck and it's only got 41k on it...

 

I would recomend the following trany cooler:

TorqFlo High Performance transmission oil cooler.

Auto Zone has a good deal on the kit.
http://www.autozone.com/Ntt,transmis...2BDE5C9979FA23

 

the guys on ram forums have generally gotten better in-town mileage by about 2mpg and about 2mpg worse on the highway. that was going from 3.92 to 4.56. cost was about $1000. depending on how much towing you do compared to how much non-towing miles you put on it...could be worth it. you'd also get limited slip/locker in doing the swap.

 

Hydra, that link didnt bring me to any products. Can you try to repost it?

and I don't think the Hypertech Max Energy is compatible with the 4.7L... The hypertech website doesnt even recognize the 4.7 as an engine choice for Durango/Dakota/Ram