3.92’s or 3.21’s for 2018 Ram 1500?

bryan28 · Nov 21, 2017

I've owned both. The 14 Sport had 3.21s and stock sized tires and my 17 has 3.92s and a 4" lift with 35s. I honestly couldn't tell that much of a difference even before the lift and 35s were installed. With the 3.21s you are still rated to tow 8k pounds and 10k with 3.92s with cc 4x4 hemi. I'd suggest if you're buying what is on the lot and not ordering, either will work just fine. If you plan to order a truck $95 for the 3.92s is a bargain.

mohemipar · Nov 21, 2017

For me personally, i am for getting the lowest gear possible in a truck. Even if you arent regularly towing, if you ever need it youll be glad you have it. If you went to the dealer and asked them to swap in a set of 3.92s after the fact the quote would probably make you **** your pants. And its like $100 bucks or something from the factory. Also, 35's or 37's are a must for me, so lower gear is a must as well.

Having said that, the 3.21s will get the job done for you and return slightly better MPG on the highway. Would much rather have 3.92's in the city though.

corneileous · Nov 21, 2017

As I said, the $95 for the upgraded 3.92’s isn’t a problem, I’m just still trying to figure out whether I really need them or not because to be quite honest the better fuel mileage is more important to me over the increased acceleration. If I towed a lot or lived up in the mountains there’d probably be no question but, I don’t do any of that. I don’t plan on putting larger tires on or lifting/leveling it. Don’t plan on towing hardly at all. This is going to be a highway truck.

If the 3.92’s really didn’t affect my mileage all that much(within reason of my driving style...lol) I would be a lot more considering of them.

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mohemipar · Nov 21, 2017

FYI. be sure to order the Limited Slip Diff...

I am certain no one here will tell you that you NEED 3.92s for what you are using the truck for. So if you are going by what you need the 3.21 is more than sufficient.

If you are planning a set of 35's (especially Toyos or some of the heavier tires) they will put some hurt on the truck will 3.21s though.

Salsa · Nov 21, 2017

My truck has 3.21 gears and runs just fine. The only thing I wanted to be able to tow is my 6X12 V Nose MC trailer. It tows perfectly behind my 25' Motorhome with a MB V6 so I knew it will be fine behind my Express. My truck isn't even broke in yet with 1,200 miles and I get around 13mpg stop & go around town. Out on the Interstate @ 80mph it's about 20mpg. The other thing I tow is my 20' pontoon boat which is actually pretty light with a tongue weight of 285lbs. Keeping a truck for a lot of years like me, 1 to 2 mpg adds up especially on long trips.

I'll have to see what I lose for mileage when I get rid of these crappy GY Wranglers and put on the BFG KO2's.

Good Luck.

corneileous · Nov 21, 2017

mohemipar said:
FYI. be sure to order the Limited Slip Diff...

Oh yeah. That’s a given there, although I’m still curious how that limited slip will work with the traction control, tho. I was always under the impression that that was why my current truck doesn’t have the anti-spin diff, because it has the ESP.

I am certain no one here will tell you that you NEED 3.92s for what you are using the truck for. So if you are going by what you need the 3.21 is more than sufficient.

Um, it kinda seems that way but you know, it’s cool, there’s nothing wrong with that. If a lot of people really like and prefer the shorter gears then there might be a good reason to go that route anyway.

If you are planning a set of 35's (especially Toyos or some of the heavier tires) they will put some hurt on the truck will 3.21s though.

Respectfully, no. It’s already going to be riding on 33’s so that’s more than enough for me. Anything larger than that in my opinion is just for looks or to serve a greater purpose for more than I’ll ever use my truck for.

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huntergreen · Nov 21, 2017

Corneileous,. I have the 3.92 and am happy with them. Bought off the lot and that's what it came with. Either gear ratio would have been fine for me. I have read and found to be somewhat true, in my rural area with very little flat road driving, the 3.92 holds the gear better, less searching for the correct gear and keeps the MDS activated longer. Never owned the the 3:21 to give my own comparison.

corneileous · Nov 21, 2017

huntergreen said:
Corneileous,. I have the 3.92 and am happy with them. Bought off the lot and that's what it came with. Either gear ratio would have been fine for me. I have read and found to be somewhat true, in my rural area with very little flat road driving, the 3.92 holds the gear better, less searching for the correct gear and keeps the MDS activated longer. Never owned the the 3:21 to give my own comparison.

See, this is why I started this thread. I never thought about the lower gears helping to keep the motor from working so hard so that it may hold a gear better and maybe keep the MDS/VVT stuff activated longer. I guess I could be guilty of looking at all this from a more old school perspective in thinking that years ago we didn’t have all this technology to aide fuel economy and that if you wanted less fuel consumption, you’re better off getting the higher gears unless you did a ****-ton of towing or off-roading that would justify shorter gears.

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JPT · Nov 21, 2017

If you have the choice, get the 3.92's, if you don't get the 3.21's. Either way you will be happy with either, but if you can get the 3.92's. Seems members with the 3.21's get like 1-2 mpg difference, so there isn't some huge savings by getting the 3.21's.

There is a noticeable difference between the two if you drive them one after another, but it isn't like the 3.21's are slow.

shadowhawk · Nov 21, 2017

corneileous said:
See, this is why I started this thread. I never thought about the lower gears helping to keep the motor from working so hard so that it may hold a gear better and maybe keep the MDS/VVT stuff activated longer. I guess I could be guilty of looking at all this from a more old school perspective in thinking that years ago we didn’t have all this technology to aide fuel economy and that if you wanted less fuel consumption, you’re better off getting the higher gears unless you did a ****-ton of towing or off-roading that would justify shorter gears.

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if that were true, wouldn't mileage be BETTER, not worse?

corneileous · Nov 21, 2017

shadowhawk said:
if that were true, wouldn't mileage be BETTER, not worse?

Which part, the part about lower gears making a motor not work as hard, thus translating to less fuel consumption or the part about lower gears in newer technology motors that would keep a higher gear more often resulting in longer durations of the 4-banger mode?

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corneileous · Nov 21, 2017

JPT said:
If you have the choice, get the 3.92's, if you don't get the 3.21's. Either way you will be happy with either, but if you can get the 3.92's. Seems members with the 3.21's get like 1-2 mpg difference, so there isn't some huge savings by getting the 3.21's.

See if that was the case, if all I would primarily see is just a 1 to maybe 2 mpg loss with the lower gears, I don’t think I’d be too awfully concerned about that. If I was driving a hundred miles a day, then yeah, but I don’t.

There is a noticeable difference between the two if you drive them one after another, but it isn't like the 3.21's are slow.

I really wish i would have payed attention to what gear ratio that Laramie Longhorn had but I didn’t. I was too focused on the air suspension but since it was a dealer-stock order, I wouldn’t be surprised if it had the 3.21’s and I held itself well. No complaints at all.

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shadowhawk · Nov 21, 2017

corneileous said:
Which part, the part about lower gears making a motor not work as hard, thus translating to less fuel consumption or the part about lower gears in newer technology motors that would keep a higher gear more often resulting in longer durations of the 4-banger mode?

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the not working so hard translating to better MPG.

joeygster · Nov 21, 2017

I've got the 3.92's & love them. I have a 60 mile (there & back) daily commute mostly highway driving. I'm not overly concerned about a slight difference in fuel economy.

I got the 3.92's because I wanted performance at my fingertips and yo get it in spades with the 3.92's.

I've driven the exact truck I have with the 3.21's and the performance and power difference is night & day.

mohemipar · Nov 21, 2017

The majority of dealers order trucks with 3.21s. Occasionally you will find a dealer stock 3.92s. Same as with HD trucks. 4.10s are close to impossible to find on most dealer lots.

corneileous · Nov 21, 2017

joeygster said:
I've got the 3.92's & love them. I have a 60 mile (there & back) daily commute mostly highway driving. I'm not overly concerned about a slight difference in fuel economy.

I got the 3.92's because I wanted performance at my fingertips and yo get it in spades with the 3.92's.

I've driven the exact truck I have with the 3.21's and the performance and power difference is night & day.

Hmm.

Yeah, I’m really not all that concerned so much with fuel mileage myself since I won’t be driving it near as much as the rest of the world would be driving there’s, especially since it oughtta be worlds better than my 2008 no matter which gears it has but, whenever I take a long trip somewhere like I did back in July up to Colorado, that nearly 300-dollar fuel bill I had was pretty steep. lol. Course, I wasn’t driving slow, I hardly ever do but on long trips is where I think I would appreciate that one to two-mile extra mpg’s.

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shadowhawk · Nov 21, 2017

sounds like you've decided on 3.21.

corneileous · Nov 21, 2017

Salsa said:
Salsa said:

My truck has 3.21 gears.... Out on the Interstate @ 80mph it's about 20mpg.

Click to expand...

RamInfo said:

Truck in my sig has 3.92s and routinely makes between 18 and 20mpg running 70-75 on cruise.

Best,
DG

Click to expand...

With responses like this, I definitely have some thinking to do...[emoji41]

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corneileous · Nov 21, 2017

mohemipar said:
The majority of dealers order trucks with 3.21s. Occasionally you will find a dealer stock 3.92s. Same as with HD trucks. 4.10s are close to impossible to find on most dealer lots.

That’s what I’m thinking too that, that one I test-drove the other day probably did in fact have the standard gearing. Now I’ll just have to figure out what mine is but it probably won’t matter because it has the 5-speed auto. I dunno, I’ll still research into it because now it has me curious.

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mohemipar · Nov 21, 2017

If the one you test drove is on the dealer's website, grab the VIN and plug it into https://www.ramtrucks.com/webselfservice/ram/ equipment listing and you'll get the build sheet.

3.92’s or 3.21’s for 2018 Ram 1500?

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