Gear Ratio Question?

[Adams2013]

I Currently Have 3.55s
With The 6-Speed Tranny
I Am Thinking About Going To

3.73s Or 3.92s

Is This Something I Should Consider Or Just Leave Alone

And If So What's A Gear Swap Cost?

 

[kschaefer426]

why do you want to do a gear swap? is ur truck 4x4?

 

[Harrisb]

OK, I've seen many threads on gear swaps and for 2012+ guys I consistently see "it's too hard and too expensive". This is almost always in reference to using 4.10 or 4.56 gears, not one of the available factory ratios for 4x4.

So my questions are, what parts are involved to say swap in a factory 3.92 with LSD? What would the labor be like?

I'm very interested in factory 3.92's, cost is always something that the purchaser defines if it's "too expensive". Something is always worth what an individual is willing to pay.

 

[TXCMark]

For the rear, an OEM 3.92 ring/pinion will run around 350. In Houston, labor is around 400 and another 100 for an install kit. So 850+tax. I assume it would be about the same for up front.

I'd advise to go 4.10 if you're going to swap. You lose a little mpg on the highway, gain allot of mpg everywhere else, better/easier acceleration. Its an OEM size for the rear, and I am told aftermarket 4.10s are direct fit up front, so probably $100 or so cheaper to do the front.

 

[Harrisb]

If I read correctly the 4:10's are not a direct fit in the front on 2012+ models. RAM welded the gear on so it basically requires a either machining or a whole new carrier. I may have misunderstood but I seem to be hearing that anything other than stock gears for 2012+ 4x4's is costly due to this (no aftermarket options without machining). I'd be completely fine with 3.92's and lsd as I already have the 8sp which has a fairly good ratio on the first couple of gears to begin with.

 

[TXCMark]

If I read correctly the 4:10's are not a direct fit in the front on 2012+ models. RAM welded the gear on so it basically requires a either machining or a whole new carrier. I may have misunderstood but I seem to be hearing that anything other than stock gears for 2012+ 4x4's is costly due to this (no aftermarket options without machining). I'd be completely fine with 3.92's and lsd as I already have the 8sp which has a fairly good ratio on the first couple of gears to begin with.

I'm sure you are right about the 4.10s not fitting up front on 12+. RAM keeps jacking with the ring gears & carriers on these things. I was told by a dealer yesterday that they revised the rear carrier again in the '13s, and now '12 rings arent compatible with '13s.

 

[Harrisb]

Did some more reading....the 12+ ring gear is welded to the carrier in the front, thus requiring a whole new carrier or a donor 09-11 front and driveshaft (driveshaft is different too). Rear is doable. It basically limits us to stock 4x4 ratios unless you don't mind spending 3k plus.

My question is more around what it would cost to swap in factory 3.92's w/lsd? I've yet to see that info here as most want 4.10's or 4.56

 

[TheSatinPumpkin]

Call around for prices so you hear it from the source.

Sent from my ASUS Transformer Pad TF700T using Tapatalk 2

 

[Harrisb]

I live in Ottawa so finding a place that specializes in gears is proving difficult and I really don't want to get reamed by the dealer, figured there must be people in this forum who have already looked into it. Heck, the VERY complicated axle, driveshaft swap plus gears has been beat to death.....this I would figure is closer to standard procedure

 

[Hemi450hp]

On a 12+ 2wd, the rear gear swap is simple as long as you go with the factory 3.92 or factory 4.10's. The factory ring/pinion does cost more than the aftermarket, but they are a direct swap and wont require any modification.

If you are 4wd and want to upgrade to 3.92's (highest factory option for the 4wd), then you will still need a new 12+ front carrier because the ring gear is welded to your current carrier. It would be much cheaper than going to an 09-11 front with aftermarket gears, but it is still not a cheap upgrade. IMO, it is not worth the cost if only going from 3.55's to 3.92's. If you are going to spend the money to make the swap, then I would do it right and go with no less than 4.10's.

 

[TheSatinPumpkin]

Post #6 indicated the rear design was changed again so the prior year is not interchangable. However there is a thread on a guy doing 4.10 installed on his 2wd 2013.

Sent from my SCH-I405 using Tapatalk 2

 

[TXCMark]

Post #6 indicated the rear design was changed again so the prior year is not interchangable. However there is a thread on a guy doing 4.10 installed on his 2wd 2013.

Sent from my SCH-I405 using Tapatalk 2

Yes, just to clarify, the change did effect my year oem diff ('12 non-lsd carrier/gears). I dont know if it effected all '12+ 9.25ZFs / I just assumed so because they revised the ring gear part numbers too. Here is what the dealer in Illinois sent me

..."part# 68050784AH has been discontinued for service and is replace by a upgraded #68050784AI carrier. Unfortunately the updated carrier (according to Mopar) is not compatible with the the old ring and pinion and must be upgraded also."

My truck has the AH version, and he said there were none in the states, only AIs. There are probly still old version rings still out there tho, i didnt check, I'm doing the 4.56 swap

 

[HLram]

I am about to do 3.92s in my truck on my next days off. I have 3.55s from the factory. The 4x4 shop here quoted me a price of $650 each axle for 3.92s. $1300 for lower gears is worth it to me. I have never understood why everyone always says not to bother just going up one gear ratio, they say to go up to 4.10 plus. Well, I don't want to be turning that many rpms running 75-85 mph. I travel alot and I just want the truck to be like Ram should have made it from the factory. I don't plan on running 37'' tires so I will be very happy with the added peppiness the 3.92s will give me. And yes, it will be noticeable. I have an 07 model with 3.92s and its noticeably stouter off the line. So to the OP you get what you want and save a thou or more on machining etc and get the 3.92s like you want. We're not all building drag racers.

 

[Hemi450hp]

Heath, are they installing used parts or new? Also, do they know that they are going to have to replace your entire front carrier? Parts alone for a 4wd gear swap (for the standard 9.25 rear and older 8" front) using cheaper aftermarket gears run about $700 and labor is generally $600-$800. If going with new factory gears, then the price of the rear gears goes up about $150. If having to replace the entire front carrier assembly, then that is going to tack on another $1000-$1300.

I hope the shop understands what kind of swap they are looking at. If they are doing all this for only $1300, then you are getting a steal of a price. I don't know anyone that has successfully swapped gears in a 2012 4wd for less than $2000. Only way to make it happen is if you find some quality parts at a scrapyard and a shop that is reasonable on the labor rate.

 

[HLram]

yeah $2000 is what I was expecting too. I was pleasantly surprised when he quoted me 1300. They are supposed to be new parts with a better warranty than the factory gears is what he told me. It is the biggest and probably the oldest 4x4 shop in town / area and they do ALOT of the rock crawlers and big ole jacked up trucks, so I figured they knew what they were talking about. lol. He said it would be a few hundred more if the seals etc needed to be replaced. Still cheaper than what I was expecting. I cannot remember the brand of the gears. Sorry.

 

[HLram]

also I thought the factory diffs were ok taking factory gear ratios like 3.92s? I am willing to pay 2000 for 3.92s either way tho. I just want a little extra umph. Just like the OP.

 

[Hemi450hp]

The problem with the 2012 is that the ring gear is welded to the carrier on your front diff. This means you cant just throw a new ring and pinion in the front. You have to swap the complete front axle out with a factory unit that has 3.92's to complete this swap...the front axle alone is going to run you about $1500 in parts alone. This may be something to take up with the shop before they take your truck apart. If they are not aware of this on the 2012's, then they are not going to be happy when they pull the front cover off.

$1300 is a decent price for a standard 4wd gear swap when you don't have to machine the rear or replace the front diff. I'm just not sure that the shop fully understands what needs to be done to complete this swap on your truck.

 

[HLram]

Ok so the actual factory gears are the only ones that'll work without machining then? I thought it was just the gear ratios themselves that would work. Well, if that is the case then that shop probably has not done a 2012 1500 yet then. Damn. I was pumped with that price! I will call them in the morning. BTW, you ship my brake pads yet? lol.

 

[HLram]

I think he told me Yukon on the brand name of the gears. Does that sound right?

 

[Reaper]

HLram, any action on this gear swap?

I'm in a similar predicament,
and would love to swap in 3.92's.

If not I guess I'll see how much the front 3.92 carrier will cost from the dealer.