What gears do I need?

ShinerBock wrote:
I have no dog in the fight of 3.73s or 4.10's with the 6.4L, but I would recommend the Tracrite helical gear limited slip that these trucks come with. It reacts quickly making it much easier to take off in slippery conditions. I have a friend who has a similar truck to mine without it and he has to do a lot of throttle manipulation in similar situations. I just hit the throttle and go. If it slips, then the Tracrite kicks in and off I go.

+1 on this.

The Tracrite should prove superior. I have similar 2x Eaton Truetrac and they are still amazing with 125,000 miles on them.

6.4 and 7,000 pounds... the gearing will not matter much but I would not avoid 4.10 if the truck you want has it.

Given the choice, I'd always opt for the higher (numerically) gears. I would also get the limited slip.

At 7K# either will probably do fine. My truck has the 6.4 Hemi and 4.10, but I tow a high profile 5er that weighs about 12,500 #. It has done a fine job in the eastern mountains (TN and KY areas) and over a 2,000 mile trip I averaged 8 mpg towing the fifth wheel. My advice, if you ever think you may want to go larger with the RV, then get the 4.10. If anything, with the 4.10 you will get a little better mileage around town and a little worse on the highway (about 1 mpg).

NO NO NO to the 4:10. It is uneccessary. I had this truck with a 3:73 and it is fine. What affects you much more than the rear end ratio is the 6 speed transmission which gives you gearing plenty low enough to start from a dead stop on any incline you will ever find yourself on.

Further the 4:10 will make what is not great gas mileage much worse.

If you really want to avoid any issues at all just spring for the TDSL Cummins version. That is what I traded my 5.7L Hemi on and have never regretted it.

I have the 4.10's with my 6.4 2500. Love em. Around town it shifts seamlessly. When towing my 9300 lb 5er they're great. I specifically looked for only 4.10 trucks after reading about the gear ratio oddities. Glad I did. I don't notice the 1-2 drop off around town and when towing it's there but not in a bad way. In the real world it's only an issue on occasion during a trip.
I'm guessing with the heavier loads it would be more noticeable. For the OP's 7000 lbs, probably a non issue.

4:10 on Chevy, and Ram, 4:30 on Ford, and when you go up a tire size later they all go back down a bit.

I have a 6.2L Ford with 3.73 pulling an 8K trailer and it does find in every situation I've pulled, even in the hill country in Pennsylvania. Of course the hill country in PA is a far cry from the hill country in CO so maybe someone that has done some trailering in the really high elevations will comment.

I have no dog in the fight of 3.73s or 4.10's with the 6.4L, but I would recommend the Tracrite helical gear limited slip that these trucks come with. It reacts quickly making it much easier to take off in slippery conditions. I have a friend who has a similar truck to mine without it and he has to do a lot of throttle manipulation in similar situations. I just hit the throttle and go. If it slips, then the Tracrite kicks in and off I go.

Laws of physics...changing gear ratios on any transmission, whether it be the main tranny bolted to the ICE, Transfer Case, differential, etc....changes the torque multiplication by that ratio change

Going from a 3.73 to a 4.1 will have "MORE" torque multiplication by about 10% MORE torque

Analogous to a 2x4 used with a fulcrum. There are two lengths and their interaction is the leverage ratio

Ditto to a block and tackle for old world ships or my windsurfer down-haul pulley system. There is an increase in forces...when you pull on the main rope...the pulleys will multiply that force by the 'lesser' amount of travel between the hook-up points

On a gear set, the pinion turns 3.73 times for each turn of the ring gear....more pinion RPM's for one ring gear RPM. Change to 4.1's and the pinion will turn about 10% more RPM's per single ring gear turn (RPM)

Since more pinion RPM's and still "ONE" ring gear RPM, there is more torque per axle turn....and more HP because of this formula to figure HP.....HP = RPM x Torque / 5252. More RPM's will have more HP. Torque from the input pinion will remain the same.

But...there are many other attributes that most don't take into account

So to take the gear ratio change without those other factors is to discuss/view this gear change out of context

Just 'some' of the other factors are

• TV attributes
• ICE attributes, mainly the torque/HP curve
• Up stream tranny gear ratios and which gear is in discussion
• Transfer Case gear ratio, if this is a 4x4/AWD
• Tire dia, best to use "rev's per mile" to level the playing field
• Trailer type, shape, weight, and a big ETC
• Terrain...incline, ambient temps, another big ETC
• Computers & how their software algorithms/look-up tables look like...even tuners...and another big ETC
• ETC, ETC, ETC

Finally how you drive...and/or just looking for justification of whatever the OP wants to hear...

deltabravo wrote:

old guy wrote:
get a locking rear end also with the 4.10's

Does RAM offer some sort of locker or limited slip in the rear axle?

You have no choice anyway, when you option the 4.10's you automatically have to add the limited slip.

They don't offer a "locker".

To answer the question...in any gas truck I was buying specifically to tow a camper with, I would option the highest (numerical) gear ratio they offered me. So I would definitely get the 4.10's in the ram.