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Discussion Starter #1
Found a 2014 1500 Laramie Longhorn I am very interested in with 4-corner air, tow mirrors and integrated brake controller, but has the 3.21 rear axle.
Anyone have a ballpark idea of what it would cost to have a transmission shop swap out to 3.92?
Thanks
 

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Is it 2WD or 4WD? If it's 4WD it probably makes sense to find one that already has the 3.92 in it already.
 

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Discussion Starter #3
It is 4 wheel drive. My 2005 Suburban is still doing the job of pulling my travel trailer and plowing in the winter, so even though I am getting itchy to buy a new or new to me Ram 1500 think I will wait awhile.
 

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I drove both before i bought mine, with the 8 speed trans there is not much difference in the two. If if was a 6 speed trans I would of went with the 3.92, but I picked the 3.21
 

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if its a 4x4 you would have to change both front and rear axles... just buy the truck with the gearing you need and save yourself the hassle..
that being said, my 3.21 8 speed tows really well(7000lbs) 28ft travel trailer.
 

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What is the size of your trailer; does it require 3.92 to be able to legally tow it? When I got my 2016, I went in wanting the 3.92 and limited slip but not in a Sport trim, which wasn't available on the lot. I drove a 3.92 black express, which is the truck I went to the dealer to test drive, but it didn't have limited slip. I just went through installing LS in my 2014 not too long before and it cost about $1700, so I wasn't doing that again.

My wife spied a BigHorn that caught her eye, but it only had 3.21 gears. I don't tow heavy enough to NEED the 3.92 and the difference between them driving unloaded was nil on back to back test drives with heavy acceleration. My trailer is about 5800# dry.

Both trucks were new with under 10 miles on them, so the difference may be become more apparent as the trucks break in. The difference would hopefully be appreciable when towing.

That being said, I would not buy a 3.21 truck with the intent on swapping to 3.92 gears, it is going to be an expensive headache because of the front axle.
 

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If your trailer is 8000lbs or less, you will be wasting thousands of dollars to swap to 3.92s
 

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I did a bunch of research on this before I bought my 2014 and it boils down to your gear ratio. the 6 spd had a higer (numerically lower) first gear ratio and overdrive ratio than the 8spd. that transmission should be paired with the 3.92 gear. the 8spd seems to be targetted to the 3.92 ratio. I got an outdoorsman package truck which comes with the 3.92 and limited slip dif. when I'm on the highway above 70 she sings pretty high and when I'm at a stop light pulling my 5k lb boat it's got more snot than my old f150 did unloaded! at this point I can confidently say there is no real reason to have the 3.92 gear with the 8spd.
 

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I did a bunch of research on this before I bought my 2014 and it boils down to your gear ratio. the 6 spd had a higer (numerically lower) first gear ratio and overdrive ratio than the 8spd. that transmission should be paired with the 3.92 gear. the 8spd seems to be targetted to the 3.92 ratio. I got an outdoorsman package truck which comes with the 3.92 and limited slip dif. when I'm on the highway above 70 she sings pretty high and when I'm at a stop light pulling my 5k lb boat it's got more snot than my old f150 did unloaded! at this point I can confidently say there is no real reason to have the 3.92 gear with the 8spd.
The 6 speed and 8 speed have the same 0.67:1 top gear ratio
 

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If your trailer is 8000lbs or less, you will be wasting thousands of dollars to swap to 3.92s
I agree. The 3.21 tows my trailer easily and confidently. I would like to see TFL do an Ike test with a 7500# trailer with the 3.92 and 3.21 Ram. I would like to see the numbers and hear the critiques, not because I expect the 3.21 to be better, but I am curious how much difference there would be in shifting, fuel consumption, descending, and driveability.
 

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I have a 2008 Ram 1500 4x4 with 5000lb air bags with 3.92 gears. I had absolutely no problem pulling a 36ft 10,200 lb 5th wheel. We sold it and got a new 36 ft pull behind 9000 lb dry weight and it does even better. Gas mileage sucks (6 to 7 mpg) when I pull the camper and still sucks (10 mpg) when not pulling. Highway speed really sucks above 80. Going from 80 to 90 mph takes like 10 minutes but I love to setup..
 

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Lots of of stress.
Love to get peoples knowledgeable opinions.
Was right in the middle of purchasing a 2016 Dodge Ram 1500 4x4. Crew cab 6’4 bed. Truck has a factory installed 4inch lift and off-road tires.
I need to immediately haul a 8.5 x 20ft car hauler trailer loaded heavy guessing around 12,500+ lbs. I need to haul this about 3300 miles.
Has the tow package. But only has the 3.21 rear end, truck also has 58k miles on it . The people at dodge does not suggest it. My dad say I will destroy the truck. I cancelled the deal but still sitting in parking lot undecided. Please help!
 

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It was going to be $2200 for my 4x4 to be changed over from 3.21 to 3.92 gears but that was also with an LSD put in at the same time. I opted for just the LSD swap for $790.
 

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Lots of of stress.
Love to get peoples knowledgeable opinions.
Was right in the middle of purchasing a 2016 Dodge Ram 1500 4x4. Crew cab 6’4 bed. Truck has a factory installed 4inch lift and off-road tires.
I need to immediately haul a 8.5 x 20ft car hauler trailer loaded heavy guessing around 12,500+ lbs. I need to haul this about 3300 miles.
Has the tow package. But only has the 3.21 rear end, truck also has 58k miles on it . The people at dodge does not suggest it. My dad say I will destroy the truck. I cancelled the deal but still sitting in parking lot undecided. Please help!
You need a 2500 for that trailer more than you need a 1500 with 3.92s
 

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It was going to be $2200 for my 4x4 to be changed over from 3.21 to 3.92 gears but that was also with an LSD put in at the same time. I opted for just the LSD swap for $790.
Where did you get an LSD done for 800 bucks ? When I asked my dealership about a swap, they quoted me over $2K.
 

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Where did you get an LSD done for 800 bucks ? When I asked my dealership about a swap, they quoted me over $2K.
Find a local shop. If you need a starting point look for an off-road or a hot rod shop and if they can't do it they should be able to tell you who can. I paid around that for labor on a LSD swap on my 2014 when I had it.
 

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Where did you get an LSD done for 800 bucks ? When I asked my dealership about a swap, they quoted me over $2K.
It was a local shop. They only work on drivelines. I posted a pic of the invoice on a different rear end thread.
 

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I find myself in a bad situation. I am hoping the dealership is going to figure out what to do. We bought a new 2020 1500 limited on Thursday. The purpose of this truck it to tow my horse from FL to CA in the early summer and back in the fall. Over the Rockies and long-distance driving. We told the sales person we needed the max towing capacity of either 11,100 or the 12,000 on the V8 hemi e-torque gas or diesel. He showed us a demo truck (no sticker shown) and said it had everything we needed including the trailer-tow package. So we trade in my car and away we go in the beautiful new truck. The next day (yesterday), I was looking at the sticker given to us with our signed paperwork and saw the axle was only 3.2 instead of the 3.92. And at looking at various trailers and checking the combined gross weight of the truck/trailer, had a nasty surprise of seeing it was not going to do the job. And, upon checking the VIN, saw that the towing capacity is rated at only 8100. I've talked to the manager today and he says he is going to see about changing the axle from the 3.2 to the 3.92. Is this practical and is it going to devalue my truck? Or should we push them to take this one back and give us the same thing but with the 3.92 axle?
 

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I'd push them to take it back. There's a sticker on the door that stipulates the maximum Gross Vehicle Weight Rating GVWR. Just changing the axle ratio will not change that sticker, and although the chances are very small that it could be an issue, the chance does exist.
 
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