3.21 vs. 3.92

[Zeronet]

Questions for 3.21 gear vs 3.92 related to down shifting at rural or interstate highways speeds. I’d really appreciate your experience and thoughts on this.

-What gear do you have?

-Does your truck like to downshift for slight or moderate acceleration while cruising?

-Does your truck downshift occasionally when climbing a highway overpass?

-Do you ever find yourself locking out 8th gear to keep the truck from shifting a lot in areas with small hills?

Anyone else have input on this?

 

[Rustydodge]

I would always recommend if you're actually questioning/considering "3.21 or 3.92" to go with more gear and get the 3.92.

I've always heard fuel difference is minor advantage to 3.21 on highway, minor advantage 3.92 in city.
I've never heard anyone seriously regretting going with 3.92, much less paying to swap down to 3.21..
3.92 better if you're ever going to get heavier, larger, wider tires
3.92 better if you're going to lift/level
3.92 better if you are going to tow
3.92 a little more effortless off the line
3.92 a little less downshifting
I also think, 3.92 will have a little more "engine braking" when downshifting up to a stop, which saves brake wear.

I have a durango RT (3.09 i think) with 32" Falken AT3W. It does fine, but definitely notice when i switch back to stock tires every winter. It also downshifts out of 8th much more frequently than my truck, and the truck has much worse aero, is heavier, and has 33s (soon to be 34s with a little lift).

3.92 in the truck is noticeable how much closer the lower gears are when accelerating

 

[Gatornation9999]

I was in the 3.21 camp for a long time and actually went with it in my original build. But then i did some more research and went and re-rest drove a 3.21 and a 3.92 and updated my Build with a 3.92.

Ultimately, I will not do a lot of towing, don’t plan to lift the truck and will drive highway miles mostly. However, when test driving the 3.92 was noticeably more responsive off the line and in high-way acceleration.

As I did more research, it seemed that once the engine broke in the 3.92 would be more likely to shift into MDS and / or ECO more quickly than the 3.21. So I think the trade-offs will be minimal under my normal driving conditions, but when I do tow it will be more of and advantage.

 

[devildodge]

With today's 8 speed transmissions and the way they learn your driving...I feel that a person with 3.21 and a person with 3.92 will on average get about the same.

A person who drives conservative will get better with 3.92 than a person who drives aggressive with 3.21.

The only way you will see a larger increase with 3.21 over 3.92 is on flat highway driving at or below 65mph.

It really is just a personal thing. If you are using the truck as a sedan, by all means get the 3.21. If you are using it as a tow or work pig, getthe 3.92.

Plenty here have the 3.21 and it tows fine. Plenty here have the 3.92 and it gets decent mileage.

It is just like all the other debates, eTorque or not, anti spin vs eLocker, 4wd vs auto 4wd. Each has benefit and each has compromise and each has a downfall.

But in today's trucks...they are so close that it really boils down to what you want to say your truck has.

You can't go wrong.

 

[Edwards]

Questions for 3.21 gear vs 3.92 related to down shifting at rural or interstate highways speeds. I’d really appreciate your experience and thoughts on this.

-What gear do you have?

-Does your truck like to downshift for slight or moderate acceleration while cruising?

-Does your truck downshift occasionally when climbing a highway overpass?

-Do you ever find yourself locking out 8th gear to keep the truck from shifting a lot in areas with small hills?

3.92
Downshifts very seldomly when cruising or oh hills/overpass. Never lock out gears as it just drives right everywhere. Now I did notice that the Eco light came on at 21 miles on the truck and it lights up often and stays on. I notice a lot of times it will remain on as I go up and over small hills and overpasses. I'm now at at 1300 miles and running 17.5MPG with 90% suburban driving/10% highway.

 

[Zeronet]

3.92
Downshifts very seldomly when cruising or oh hills/overpass. Never lock out gears as it just drives right everywhere. Now I did notice that the Eco light came on at 21 miles on the truck and it lights up often and stays on. I notice a lot of times it will remain on as I go up and over small hills and overpasses. I'm now at at 1300 miles and running 17.5MPG with 90% suburban driving/10% highway.

Edwards, thanks so much. Just the kind of info a was looking for.

 

[MSchnLoneStar19]

I will be making an order between today and Monday. Can the Gear Ratio be changed down the line.... i.e. I order the 3.92... and in a year the MPG still is at 12 - 13... can it be changed out to 3.21 or vice versa ?

 

[Zeronet]

I will be making an order between today and Monday. Can the Gear Ratio be changed down the line.... i.e. I order the 3.92... and in a year the MPG still is at 12 - 13... can it be changed out to 3.21 or vice versa ?

They can be changed. Figure $1000-1200 per axle. So for a 4x4 that’s 2 axles.

 

[MSchnLoneStar19]

They can be changed. Figure $1000-1200 per axle. So for a 4x4 that’s 2 axles.

That’s what I was thinking. Thanks for the answer.

 

[John813]

Bumping this thread after talking to the dealership.

~1,200 for parts
8 hours or 1,200 for labor.

Talking about $2,400 to swap rear end gear at a dealership.

The adviser didn't know if the gears themselves were a carry over from the 4th gens(2011+).

Going to hold off from doing it a dealer for now.

 

[Zeronet]

Bumping this thread after talking to the dealership.

~1,200 for parts
8 hours or 1,200 for labor.

Talking about $2,400 to swap rear end gear at a dealership.

The adviser didn't know if the gears themselves were a carry over from the 4th gens(2011+).

Going to hold off from doing it a dealer for now.

Had a 4th gen done at the dealership 2 years ago. Parts were $229 and labor was $850. Those are West Virginia prices. Also priced it at a Miami dealership, they wanted $1200 for labor. Parts were the same price.

Your price for parts seems high but not sure if the 4th gen parts are the same. Maybe shop around.

 

[John813]

Had a 4th gen done at the dealership 2 years ago. Parts were $229 and labor was $850. Those are West Virginia prices. Also priced it at a Miami dealership, they wanted $1200 for labor. Parts were the same price.

Your price for parts seems high but not sure if the 4th gen parts are the same. Maybe shop around.

Oh I will. Told me they will give me a discount too(since we've done consulting work there) but that was the standard pricing there anyways.

I've been on the fence about buying the rear end gears(4th gen) from Moes, but they haven't responded to my PM's(month old by now) nor my question on their page on the other forum.

 

[Hammer1]

3.55 is now available . I have had 2 truck with 3.55 and 1 with 3.92, they are very similar. My new truck has 3.21 so will see how it goes. I would get 3.92 if I was ordering again. I never saw a difference in mileage.

 

[LossPrev]

Having just come from a 4th gen with 3.21's my initial impression is that I prefer the 3.21 for daily driving. The 3.92 is noticeably faster and is fun but it eats through the gears so quickly it feels less "smooth". Hard to tell on gas mileage but so far my lie-o-meter isnt even close to what my 4th gen got. I do like that it never shifts out if 8th on the highway though.

My recommendation, like others have said, is to go with 3.21 if you aren't towing heavy.

 

[Zeronet]

3.55 is now available . I have had 2 truck with 3.55 and 1 with 3.92, they are very similar. My new truck has 3.21 so will see how it goes. I would get 3.92 if I was ordering again. I never saw a difference in mileage.

At least on the online build and price tool, as of a couple of days ago, if you select the 3.55 it makes me select the v6 engine in order to continue.

 

[devildodge]

3.55 is V6 only. Not sure why there isn't a V8 option for that. My V10 has 3.55 and it is perfect.

 

[Edwards]

If they would have offered 3.55 on V8 with ELocker I'd have been all over that.

 

[Phoon]

If i did it again I would get 3:21 gears, first is really low in these trucks anyway so getting off the line isn't a problem. I think the lower highway RPM is more of a benefit than the marginal improvement in acceleration.

Just my 2 cents from a guy that's had a few rams.

 

[trainman]

My 2019 Ram 1500 4x4 has the 3:21 and I intend to pull a 5000 lbs. travel trailer with a 450 lb. hitch weight. I don't expect to have any problem pulling the trailer with this combination. I'm retired and will be pulling the trailer no more then 65-68 MPH this should work out just fine. I've been using a Honda Ridgeline to do the job and the Honda is right at its top GVWR rating for this trailer, that's the reason for moving up to a little more power, V6 vs. V8 and 285hp vs. 395hp. If I was pulling a much larger trailer (weight) then I would have gotten the 3:92 axle, but with what I'm doing it will work just fine. Ram has rated this vehicle at much more weight caring capacity then I ever intend to pull.

trainman