What gear should I get in my new truck I'm going to order

[tony1461571]

I'm going to order a 2014 Ram 3500 DRW with 6.7 Cummins and Aisin 6speed AT to replace my 98 3500 Quad cab that was totaled in Houston in March. I pull a 39 ft 5th Wheel about 12k dry so I would like to know what rear gear I should go with. Please give me all your thoughts. I hope to be pulling a lot in the winter snowbird. So give me your input.

 

[AH64ID]

With the double OD's of the Aisin (and 68RFE) I cannot think of a single good reason to not get the 4.10's. Even with 4.10's the truck is only turning 2235 at 80 and 180 at 60, both of which are overly acceptable for a truck with a 29K lb tow rating.

Sure the 3.42's and 3.73's will pull your load just fine but the mechanical advantage of 4.10's is 20% and 10% more respectively and that makes a difference when pulling.

 

[RustyJC]

The mechanical advantage offered by the 4.10s combined with the "liveability" of the double overdrive ratios (5th & 6th gears) of the Aisin make the 4.10s a natural for me. I tow the 5th wheel in my signature (16K GVWR) and love the 4.10s both loaded and unloaded.

Rusty

 

[PC12Driver]

I have the 3.73s in my '12, and just got back from a 750 mile trip with our Silverback 35QB4 (40', 13k dry). If I were to get a new truck I'd probably stick with the 3.73s, or possibly consider the 3.42s. I feel the 4.10s would be unnecessary.

At 55mph I'd lock it down to 5th to keep the rpms around 1,800. It could pull 6th on the flats @55mph, but even small hills would cause a downshift. There was little downshifting in 5th. At 65mph I could run in 6th with minimal downshifting. Going over the big hill northwest of Chattanooga on 24 (3-5% for several miles) I had it locked in 5th @ 60mph and it charged up the hill, nowhere near downshifting.

I suppose if I spent more time around 55mph or I lived in the mountains (towing what I do) I'd go for the 4.10s, but for what I'm doing they're overkill. I'd consider the 3.42s for the steep overdrive when bobtailing, but I have a feeling I would have to lock it down to 5th with the trailer in tow (effectively 6th with 4.10s). But then again, I only have the "little" 800 ft/lbs engine, not the big 850.

 

[tony1461571]

Thanks for the info am leaning towards the 4.10. I pulled for a long time with my 98 Bought it new But didn't know enough to get, the taller gear but would have been better back then. I'm not up on what's good for the newer 6.7. But looking to using it thanks.

 

[BILLUA]

I pull 15k In the mountains out west here and the 4.10's work great! Instead of lugging or having to lock out a gear in a 6 speed trans it will only downshift on the largest of hills and highest of density altitudes. The exhaust brake works awesome!

I just got done towing 6,000 lbs from Vegas to Amarillo and almost 12,000 on the return. I got 13mpg eastbound and 11mpg westbound.

I ran where I could up to 75mph. At that speed, I'm turning 2100 Rpms.

Caveat, my truck is not my daily driver and is used 95 percent of the time towing something. Does the mileage suffer with 4.10's towing 15k in the mountains? I doubt it very much...

Have fun! These 4th gens are nothing short of awesome!

 

[Cummins12V98]

4:10's for sure. Most people go bigger with their next RV!

I tow 28K combined with 3:42's and it does a fine job but my 15 with rear air ride will have the 4:10's!

 

[MelvinPierce]

I have what you are ordering. I got the 3.73's. I pull a 19K toy hauler, grossing out at just over 28K. It pulls it real good! I would NOT get the 4.10's.

 

[tony1461571]

Again, thanks for all the input I will keep looking and listening. I plan on ordering my new truck in about a week. I know that gear selection is all in the use as well as the user the places we want to go I think the 4.10 will be better.

 

[rrl989]

With 12K you can get any available ratio, my 3.73 is rated for 24K. I'll bet you'll pay in mpgs if you drive empty often with the 4.10s.
If fuel cost was a non-issue, I'd get the 4.10s of course.

 

[gsbrockman]

I have 3.73's in both my 2013 & 2014 Aisin DRW trucks. For me.....it's the best tradeoff for towing and fuel economy. I've driven a 4.10 / Aisin DRW truck, and that combo will put a on your face.

 

[AH64ID]

I would like to see a real world side by side mileage test of all 3 trucks. Set them up 1 mile apart and drive, city and highway. I bet the difference isn't nearly as much as people want to think it is.

 

[ARedmon]

I own a 2014 RAM 3500 Laramie Longhorn Dually with Cummins and Aisin. I ordered mine with the 3.73 gears and I have no complaints. I also pull a 5th Wheel Camper behind mine. The Camper is a 34 ft Crossroads that weighs about 12,000 lbs also. The 3.73s work great and I'm getting a bit better mpgs than I though I would.

 

[SnoKing]

If you mostly tow I would get the 4:10's. If it is a daily driver I would get the 3:73's.

Chris

 

[KYOUNG]

I think the 3:73 is fine, if I need it to be a 4:10, I shift it to 5th or even 4th if needed.

 

[RustyJC]

The value of the mechanical advantage of the 4.10 isn't at cruising speed, it's during startup and acceleration. In effect, it provides an extra gear with more torque multiplication than is available with 3.42s or 3.73s as I can use all 6 speeds effectively when towing, not just 4 or 5. In effect, with 3.42s, you're taking off in 2nd gear as compared to 4.10s - if you never have to start from a dead stop on a steep hillside while towing a heavy trailer, I guess the higher (lower numerical) gears might be fine, but I like the ability to have the higher starting torque, better acceleration and 6th gear cruising of the 4.10s while towing without high RPM at cruising when deadheading (thanks to the double overdrive 6th gear). There's a technical reason that GCWR goes up with the lower axle ratios - for a given rear wheel torque at a given road speed, driveline torques are reduced by the lower axle ratios.

Depending on how much you tow, YMMV, of course.

Rusty

 

[SnoKing]

AS69RC AISIN RATIOS
Gear: Ratio:
1 3.75 : 1
2 2.00 : 1
3 1.34 : 1
4 1.00 : 1
5 0.77 : 1
6 0.63 : 1
R 3.54 : 1

48RE RATIOS
Gear: Ratio:
1 2.45 : 1
2 1.45 : 1
3 1.00 : 1
4 0.69 : 1
R 2.21 : 1

68RFE GEAR RATIOS
Gear: Ratio:
1 3.23 : 1
2 1.84 : 1
3 1.41 : 1
4 1.00 : 1
5 0.82 : 1
6 0.63 : 1
R 4.44 : 1

As you can see the Aisin has a big advantage built into 1st gear. The 68RFE has a craw speed reverse. When you look at the lower gears you can see how 3.42 actually work in the SRW trucks.

3:73 are a very good middle ground spot!!! Except for extreme towing 4:10's and 3.75 1st gear is a big waste of one of your gears, move the gears up with 3:73 so they all become usable!

Chris

 

[CBari]

Mine is 3:73 and my lq horse trailer is about 18k-20k pounds depending on how many head we have in it. It does good, but I wish I had the 4:10 as mine shifts between 5th and 6th alot when the cruise is set around 72 on the interstate and I run into some hills. Friend of mine bought one a month later identical to mine except 4:10 and his trailer weights close to mine or heavier, and it does not down shift like mine. Also his empty mileage is as good as mine or better.

 

[tony1461571]

Thank you all very informative. Just when you think you know what you want and need you get more info.
That's a lot of good info Snoking it will help mostly we will be pulling with the truck. I really want to thank you all for the input. This has always been a good place to find what you need wi post more when I get my new Baby.

 

[PC12Driver]

That's kind of my thinking. The new engines have plenty of shove to get rolling with any gearset. In 5th I'm turning about the same RPMs on the highway that I did with my '01, so 6th is sort of a bonus gear. If I can use it, great (the difference between 5th and 6th at a constant speed with the 5ver behind is about .5 mpg btw), but 5th is no big deal.

Admittedly, I do have a manual trans mindset when it comes to driving, so I don't mind working the gears to get it to do what I want. For the set-it-and-forget-it crowd, the 4.10s would probably be the way to go.