I have an 06 Ram 3500 Mega Cab 4X4 with a 5.9 Cummins and a 6 spd manual trans. I am about to purchase a programmer to give me more power, but DEFINITELY need a change of gears. I have in the diffs 410 gears. I'm thinking of changing both diffs to a taller gear, such as a 342, possibly a 355. I do much more empty driving than I do towing, however I do not want to limit myself to unloaded driving only. I mostly carry 5,000 - 10,000 pounds when pulling my trailer.
Any thoughts are greatly appreciated!

 

Welcome to the site,

You did not say where you lived and or drove your truck. My 05 has the 3.73's this is a good combination of power / torque. I pull 10,000 lb trailers over 10,000' passes with no problems. Empty I av 18 to 20 hwy.

I "think" the G56 for the of 06 has a taller OD than the 05's, I'm sure someone will chime in on this. another option for you is to jump up to some taller tires.

 

It's the 07's that came with a better 6th gear. There is a code on the side of the trans to know and I'm not sure right now what it is but I do know none of the 06's have the better gear.
I also have the 6 speed and 3:73's and tow no more than 10,000 and love the power.

 

If you have a 6 speed manual in your truck you have 3.73 gears. 3.42 gears will help out as long as you don't tow but the cheapest thing to do is to slow down. The Smarty Jr will help some with MPG.

 

As long as you're not running big tires I think you'll be able to get away with 3.42's easy. Don't think they make 3.55's for AAM's.

How long are you going to keep the pickup? Will you recoup the gear swap money in mileage......ever?

 

I live in Alabama but use the truck for road trips often. I am sure the gears have been changed from factory (The tags are not on the diffs any longer). I plan on keeping the truck and driving it approx. 50,000 miles per year. I have Nitto 285/75/17 on the truck right now and do not plan on going that size tire again much less a bigger size.
I do have a cold air intake and a 4" MBRP straight pipe already. Which programmer do you guys like the most???
I had an 03 Cummins with the Edge Juice with Attitude, I LOVED it!!! But, I have heard a lot of good things about the smarty Jr./Sr.
Any advice????
I'm taking all the comments into consideration,
THANK YOU GUYS!!!!

 

Puttin' on that many miles I expect you could easily recoup that money in a year. Rough math if you could gain 2 mpg you could save maybe $1500 on fuel in a year. Makes sense to me.

You usually see guys wanting to do this and they have no clue that at the rate they drive and the type of driving they do they'll be selling the truck before they come close to recovering the cash for the swap.

Lot of smarty lovers. I enjoy mine, but the on the fly monitor tuner combo's are pretty sweet.

 

To figure out the gear ratio you could jack up the rear and spin the tire 1 revolution while counting the driveshaft rotations.

 

I have the same year model and gear combo you have. I only have about 10k on my 285/75's, and they are the best change I did for mpg....I the 3.73 rear end, and i'm averaging about 22 and change when I stay below 75. My best mileage shows up at around 69mph.

 

Nothing personal, but I absolutely HATE the "better gear".
I did not realize they had changed the OD gear untill after I took delivery.
If you like running 2500rpm on the interstate, it is great.

 

What's your speed at 2500 RPM?

I cruse 70 mph at about 2200 RPM with my 285 tires. If I had your 6th gear I would be at about 2000 IIRC

 

I bought my truck with 245/70/17's. And at 74mph, I was pushing 2500rpm. With the 285/75's, I now run 74 at around 2150.... That's with 3.73's, 6-speed, and the .81 over drive radio that is stock with the 06. Didn't the 07's come with .76 for the OD?

 

On my 07, 2500rpm is about 79-80mph IIRC.

 

Your truck came with 3.73's. If it had 4.10's it would run 2490 rpms at 70, and 2850 at 80. The OD ratio of the G56 in 06 was .79, which makes the truck drive like a NV5600 with 4.10's.

A regear to 3.42's is possible, but that's about it. Taller tires are the easiest way to lower rpms.

If you run 2500 at 77 then you don't have the "better gear" you have the 05.5-07.4 AD gearing. It's the better gear for towing, but not the better gear for empty cruising.

 

It is an AD.
Compared to the .73 of the NV trans I have driven, it is a little wound tite on the hwy.
I didn't know that the o7 had a .79 until after I got it. I was expecting the .73 .