4.11, LSD, and Super Chip confusion

[RLJ10X]

I have an 11 Hemi 4X4, with the rotten 3.55s, open differential.

I've been talking with a very reputable off road shop, that specializes in jeep stuff, but does pick ups also. I'd like to be clear on a few things before I proceed.

4.11s in an 11, front and rear are possible and aren't a major job, correct? I don't want them to get half finished only to discover that the other half is way more involved that they thought. I've heard the gears called both 4.10 and 4.11. I know that's splitting hairs, but I'd like to be able to use the proper terminology. The shop called them 4.11.

Tires are BFG AT TA KOs, 275/70/18 at 35 lbs, on black XD Crank wheels. Right now, I'm turning aprox 1650 rpm @ 65 mph. After the 4.11s, I should be turning aprox 1940, if my math is correct. Anybody with this tire
/gear combo have real world #s for me.

I already have an AirRaid CAI, which I like a lot. Is it safe to assume that fuel mileage after the Super Chips 89 or 91 Perf map, that the mpg will stay around 19 highway?

I've read that with the Super Chip device that the tranny can be made to shift more aggressively. That's going to be cool. But is it hard on this marginal tranny?

I know this has probably been covered before, but the "search" didn't yield the specific answers I seek. Thanks, RJ.

The truck is Hunter Green, and a real looker. I'd post a few pics if I could figure out how to keep them from being up side down...

 

[TylerB]

Splitting hairs is correct, but...
4.10-41 tooth ring gear/10 tooth pinion gear in the Ram's rear axle(not sure about front)
4.11-37 tooth ring gear/9 tooth pinion gear on other makes

Yes, they are possible to do, but since you have a 2011 you run into a little hiccup with the rear axle, the carrier was changed in '11 and no aftermarket company has made a gear set for a direct drop in swap yet. No problems at all with front axle, so it's still a simple swap with lots of aftermarket support. Are you planning on adding a Limited Slip Differential?

You have three options as of right now for the rear axle.
1) Use the stock rear 4.10s from 2011+ and the LSD, if you plan to add it(I have a 2011 as well, it originally came with 3.55s and LSD stock, I just added the 4.10s)
2) Have your stock or the LSD, if you plan to add LSD, carrier machined to fit older style gear sets (new holes drilled and countersunk between existing holes)
3)Use aftermarket carrier/LSD(again if you plan to add it) and gear set with the addition of replacing the passenger side axle shaft(shorter shaft which offsets carrier from the factory) with a driver side shaft to center the old style carrier in the axle housing.

RPMs will be right around 1800-1850 RPM at 65MPH after the swap depending on actual tire height.

I have no experience with Superchips, but you'll be fine being very lightly modded.

 

[fasthemiram12]

Good answer Tyler...

 

[TylerB]

I should have probably added that doing a gear swap on our trucks has no effect on the speedometer.

 

[RLJ10X]

Thanks, Tyler. Good info.

I did not want to overload the first post, I have more questions:

The shop. Moab's in Louisville Ky, said that adding a LSD would up the price $1300 because no aftermarket LSD exists and the only option is to use a Mopar unit, which is $800ish, and the axle shafts would have to be changed out as well. LSD would be cool, but I can't justify $1300 for something that I would not use very often. Any ideas?

I was also going to ask about the speedo/odo. Thanks for the preemptive answer!

4.10 it is.

Has anyone done 4.10s and regretted it? It looks like the solution to me. MPG ?

 

[Miami1500]

I should have probably added that doing a gear swap on our trucks has no effect on the speedometer.

Really? I am about to do a gear swap on my 2014 1500 and was told my speedo would be off.

 

[MiRamDriver]

Thanks, Tyler. Good info.

I did not want to overload the first post, I have more questions:

The shop. Moab's in Louisville Ky, said that adding a LSD would up the price $1300 because no aftermarket LSD exists and the only option is to use a Mopar unit, which is $800ish, and the axle shafts would have to be changed out as well. LSD would be cool, but I can't justify $1300 for something that I would not use very often. Any ideas?

I was also going to ask about the speedo/odo. Thanks for the preemptive answer!

4.10 it is.

Has anyone done 4.10s and regretted it? It looks like the solution to me. MPG ?

Well I certainly wouldn't be buying the parts from them. There are many legitimate Mopar dealers that sell LSD's at wholesale prices online. I think I paid $400 for an LSD for a 2012 and you only need one shaft if I remember correctly, it was around $150. I helped my Dad order the stuff two years ago and I have a brain injury FWIW lol.

You will certainly lose MPG with stock tires, no question there. Your get-up and go will be much better, you will tow a lot more effortlessly and your truck will be more fun to drive.

 

[TylerB]

Thanks, Tyler. Good info.

I did not want to overload the first post, I have more questions:

The shop. Moab's in Louisville Ky, said that adding a LSD would up the price $1300 because no aftermarket LSD exists and the only option is to use a Mopar unit, which is $800ish, and the axle shafts would have to be changed out as well. LSD would be cool, but I can't justify $1300 for something that I would not use very often. Any ideas?

I was also going to ask about the speedo/odo. Thanks for the preemptive answer!

4.10 it is.

Has anyone done 4.10s and regretted it? It looks like the solution to me. MPG ?

You do not need new shafts if using the stock carrier/LSD and gears, so there's one tick against them.
Sounds like you need to buy the parts yourself and bring them to them. They're most likely shopping at the dealer themselves, then adding additional markup on top of the dealers already inflated prices. I highly suggest you give Moe's a call, Matt there will take care of you.

Really? I am about to do a gear swap on my 2014 1500 and was told my speedo would be off.

Probably heard it from someone who has not done the swap, just more "he tell me" ******** from people without a clue.

You will certainly lose MPG with stock tires, no question there. Your get-up and go will be much better, you will tow a lot more effortlessly and your truck will be more fun to drive.

I actually gained MPG with stock tires after the gear swap.

 

[RLJ10X]

I'll call Moe's in the morning.

Guys, I really appreciate your straight, and for lack of a better word, blunt answers. You'll probably end up helping me a lot.

I've heard guys that have the Super Chips device have actually gained an mpg or two. I know, it's real silly to spend hundreds to pick up an mpg. But it'd be a nice bonus. Mostly what I'm after is curing the way too tall gears and that mushy slush box. I like my truck, but if they ever produce one with a 6 speed manual, mine's going to be for sale.

I know it's conventional wisdom that taller gears equal better fuel economy. I never did believe that. I think there's a sweet spot. I think ram gears their trucks so tall is because the EPA says they have to produce just so much of a certain amount/type of exhaust at a certain speed. Hence the cylinder deactivation... I've also heard that you turn that off, you get better fuel economy. Not sure about that one.

The gears and Chips are happening at the end of August. I've given myself time to learn. Much to learn....

 

[MiRamDriver]

I actually gained MPG with stock tires after the gear swap.

While unlikely for most, I could see it happening if you drive 100% city.

 

[RLJ10X]

I talked to Matt at Moe's. Wow. HUGE price difference. Stay tuned.

 

[TylerB]

While unlikely for most, I could see it happening if you drive 100% city.

The majority of my driving is interstate, granted I never drive over 70. To say I drive spirited from stop light to stop light is putting it lightly though.

I talked to Matt at Moe's. Wow. HUGE price difference. Stay tuned.

:thumbup:

 

[loveracing1988]

I'll call Moe's in the morning.

Guys, I really appreciate your straight, and for lack of a better word, blunt answers. You'll probably end up helping me a lot.

I've heard guys that have the Super Chips device have actually gained an mpg or two. I know, it's real silly to spend hundreds to pick up an mpg. But it'd be a nice bonus. Mostly what I'm after is curing the way too tall gears and that mushy slush box. I like my truck, but if they ever produce one with a 6 speed manual, mine's going to be for sale.

I know it's conventional wisdom that taller gears equal better fuel economy. I never did believe that. I think there's a sweet spot. I think ram gears their trucks so tall is because the EPA says they have to produce just so much of a certain amount/type of exhaust at a certain speed. Hence the cylinder deactivation... I've also heard that you turn that off, you get better fuel economy. Not sure about that one.

The gears and Chips are happening at the end of August. I've given myself time to learn. Much to learn....

There is a sweet spot for mileage, but it depends on how fast you are driving as well. I think the 3.21's will get the best mileage going faster than 70, 3.92's below. My theory is with the 3.92's it gets the engine a little higher up in the rpm range and allows the mds to come on more. Around town you might not notice a improvement with the mds on, but on the highway I pick up 1 to 2 mpg's with it on according to the evic. With the mds off I don't see higher than 20 mpg's but with it on I can get to 22 most times.

 

[RLJ10X]

22 in a big pick up is very good. I certainly can't argue with your 3.92s.

I'm hoping for 21 highway mpg @ 65, cruise set. What do you think?

I'm going to order all the parts from Matt at Moe's, in about a month. My savings account has a goal to be met first. Then I get to treat myself.

The dealership that's bought the truck new from, has a "branch" dealership 20 miles south. The branch dealership is still like the mom and pop place that it was before the big guy bought it. They have a really good, experienced guy that'll do the install. Their shop rates are very reasonable. I think I'm pretty much squared away.

 

[loveracing1988]

22 in a big pick up is very good. I certainly can't argue with your 3.92s.

I'm hoping for 21 highway mpg @ 65, cruise set. What do you think?

I'm going to order all the parts from Matt at Moe's, in about a month. My savings account has a goal to be met first. Then I get to treat myself.

The dealership that's bought the truck new from, has a "branch" dealership 20 miles south. The branch dealership is still like the mom and pop place that it was before the big guy bought it. They have a really good, experienced guy that'll do the install. Their shop rates are very reasonable. I think I'm pretty much squared away.

I should warn you that the numbers I was giving were the evic numbers. The highest average I have had all Highway was 19.1 on the evic which was 17.9 hand calculated. I see 22 mpg on my evic a lot going 65 but I think if I had to guess that is only 19 to 20 hand calculated. I would love to have 1 tank be a solid 20 mpg but I don't think I will ever see that high. I have 3.55's though with the 8 speed.

 

[MiRamDriver]

When my truck was stock height, with all of my performance mods - I saw 20.7 MPG hand calculated at 65. Now I'm getting 17.5 ish highway and 15 in the city.

 

[Crescent1101]

Is all this talk the same for a 2007? I want to change my gearing and throw in a LSD while I am pulling apart the differential.

 

[MiRamDriver]

Is all this talk the same for a 2007? I want to change my gearing and throw in a LSD while I am pulling apart the differential.

I don't think so at all. I had a 2006 Ram and my mileage was notably worse than what I've had with both of my 4th Gens. Then going to a 2013-2014, you have 8 speed, active grill shutters, far less parasitic drivetrain loss, electric power steering, etc.

 

[Crescent1101]

I almost bought a 2014 Express 4X4 today. They had that deployment deal going. I think with the Quad cab and my options I wanted they wanted 32.5k. The original price was 39k.