I talked to a guy last night that has the 5.9l, he basically has done the same as you have. Said the gears (4.56) made a world of difference. I think i might try the dealership to try and reprogram the shift points. Does Hypertech offer a programmer for the 4.7L?

 

It is the same towing or not in "tow/haul" or not until you get the computer "flashed" with the new program. Superchips is releasing the 04-05 HEMi programmer this weekend and it's the only one that I know of that will change the shift points. I got in on a pre-order and it's being shipped on 8/15 using the free 2nd day they offered. I'll post after I test it. It also bumps the HP up about 18 and torque about 31 ft-lbs. With my Magnaflows and K&N intake I hope I'll dyno out about 30 HP over stock or better.

 

I think you'll be disappointed if you have very high expectations that a programmer or computer flash will make a significant improvement. 3.55s are too short for the 4.7, especially if you tow anything. They are almost too short for the hemi with 75 lb-ft of additional torque.

A smaller diameter tire will also improve the torque you put to the pavement.

 

Took a trip to the Sierra Nevada's about two weeks ago in the Hemi. At 7000+ ft. altitude, I started noticing the Hemi wanting to downshift a little earlier, obviously seeking a little more power due to thinner oxygen in the air. At one point I got behind a slow truck and waited for a passing lane. My friend says to me, "Hit it!" so I completely floored the throttle. At 50MPH the thing shifted into 2nd and FRICKIN' ROARED past that sad trucker. Got back in line and he looks at me and goes, "Now THAT'S what I wanted to see from your HEMI!" You just need more HP!

I was so proud.

 

Took the truck to the dealership, seems like the truck shifts somewhat better. It doesn't shift into overdrive now until about 60mph, vs before about 30mph it seemed. Seems like it pulls more rpm's between shifts. Still lacking alot of power. My bad for not paying attention to the power vs the looks. How much are the 4.56 gears? Does JEGS carry them or Summit?

 

When you change the gear ratio of the Ram, how do you fix the speedometer so its not 10 mph off or whatever? Computer chip maybe?

 

4.56s will definitely get more torque to the wheels, but its also going to get your truck to the gas pumps a lot faster, think about it!! I would go with 3.73s or 3.92s maybe, 4.56 is a very low ratio....

 

You could pick up power by switching to the 17" wheels too. You've got a motor that's about as small as you really want to go (and still have power), heavy wheels, fuel economy gears, and a fuel-economy programmed tranny.
How do you fix it? Change the shift points, change the gears, change the wheels, or add a lot of power. They take off fine because you're running over 10:1 gear ratio in first versus about 2.5:1 in overdrive.

Changing shift points will allow your engine to get up enough revs to shift and end up in the meat of the power band, instead of lugging. If there really is a TSB about it, it's free.

Changing the gears will increase the ratio, if you go with 4.56:1 then your first gear ratio is going to be closer to 15:1 and your OD ratio is going to be about 3:1. Expect to spend about $500 for 2wd and $1000 for 4wd. I believe the dealer can reflash the ECU for odo/speedo functions.

The factory 20's are heavy, and the bulk of the mass is nearly 10" from the pivot point, compared to 8.5" for a 17" wheel. Increasing the diameter exponentially increases the power required to move a given mass, and when you increase both mass and distance it's even worse. Forged 17" wheels are the way to go. Strong and light. Keep the tire diameter the same and you won't have to mess with the speedo/odo.

Adding power is obvious. It's going to cost a lot of money.

 

You where close with your estaments but please tell me when a 3.05 became a bad highway rear ratio. Back in the days when there where no overdrives a 3.26 rear gear was considered a GOOD HIGHWAY gear to have without losing PASSING power... With out OVERDRIVES we have 3.05 rear gear ratios with 4.56's in the tail end!

I did the math .... Most importantly look at the final overal ratio's.... In a Large truck you want to have allot of "LOW END" to get your 5,000LB+ truck rolling from a stop and to be able to TOW without adding unwanted STRESS/Heat to your transmission. The problem is, untill today that is..... you have to chose ONE or the other.... Low end torque or Highway fuel economey. You where unable to get both.... Untill the double OVERDRIVE transmission that is. With our transmission you can go with a real steep gear like the 4.56's without losing MPG... In fact most people gain 1-2MPG up to 65-70MPH by going to the 4.56's. You get your cake and eat it too. I have went from the 3.55's to the 4.56's and not only can I crank out 20+MPG @ 65MPH... but I have been able to get my 60ft time to a best of 1.99 in my QUAD CAB 4.7L! I think I forgot to mention that with the 4.56's I have been WELL over the 120MPH on the speedo... "L1" to be exact... so please dont tell me you lose your top end with 4.56's!

545RFE* (2003 - 2005) transmission gearing

1st-----------2nd-----------3rd----------OD
3.00------1.67/1.50 ------ 1.00-------- 0.75/0.67

3.55's your effective ratios would be:
10.65------5.92/5.32------3.55---------2.66/2.37

3.92's your effective ratios would be:
11.76------6.54/5.88-------3.92---------2.94/2.62

4.56's your effective ratios would be:
13.68-------7.61/6.84-------4.56---------3.42/3.05

4.56's are the best of both worlds and they are a MUST in any 3rd Gen Ram!

SPEED SAFE, AIR RAM

 

I was too lazy to go find the exact ratios so I guessed 3.2 for first and .67 or .68 for OD.
A 3.05:1 would be a good freeway gear in a car that clocked in at 3500-4000lbs with stock power levels, but in a 5000 lb truck if you want to tow something it's just not going to work. I have an a727 and 4.10s in my truck Ram and it goes just fine. I can pull steep mountain passes with a ~12000lb combined weight at 60mph in 2nd gear. If I had a ~3:1 ratio I'd probably still be able to do it, but if I put it in 3rd I'd be hurting bigtime. As it is I can't do the steep hills in 3rd.
The Dakota on the other hand has a 46re with 3.92 and it's OD ratio is about 2.7:1 - It's an ok freeway cruising gear but not so great for power.