3.21 vs. 3.92 gear ratio - Ram 1500

The Critic

The Critic

Joined
Aug 30, 2004
Messages
31,938
Location
CA
I am in the market for a new Ram 1500 and I have to make on the gear ratio. Most commonly, the choices is 3.21 or 3.92.

I have no immediate plans to do any towing. The engine will either be the 5.7L V8 or the 3.0L Ecodiesel.

For my application, does the gear ratio even matter?
 
Depends on what you like. If you are never going to tow, it should not matter. But the 3.92 truck will be quicker from a stop, and might be more enjoyable around town.
 
If you're not planning to tow, the 3.21 will put a smile on your face with the added fuel economy - I get between 17-19 miles per gallon depending on traffic. My daily driving is around 60 street / 40 highway.
 
My silverado with 3.23 gears and the 4.8 V8 is silly fast already, by my standards anyway. The posi-traction really helps the 0-30.

Why not test drive both?
 
I've got the 3.21's in my 2019 Classic with the 5.7, and don't really tow anything. I think it's just fine, especially coming from a v6 Chrysler 300 that had a 2.62 rear end. Averaging high 17-low 18 for fuel economy.
 
if you get the 3.21 will it use 8th gear at your crusing speed effectively?

if you get 3.92 it will feel like you have more power, will the mpg be affected if it uses 8th gear more?

you have to remember 3.92 is not really that high with 4x4 truck size tires..

vs a 3.92 in a car (hemi charger?) etc.

I wish for even higher gearing in my jeep cherokee.. I have the highest available gearing (4cyl motor) and the highest torque motor(295ft/lb)
but it still wont go into 9th.. below 80mph.. and at 80 it doesnt have enough torque to stay in 9th except downhill.

Im not very familiar with the ZF-8 a much better transmission but if it stays in 7th with 3.21 vs 8th with 3.92.. the fuel economy should be very similar.

If it was me I'd probably lean towards the 3.92 but test drive both.

I'd also skip the eco diesel.. as much as I want to like it.. diesel costs more, $5000 upfront ,more issues than gas, and the hemi has more power.

although the pentastar v6 is 300hp is also a fine choice if you want MPG.
 
For what you are describing, it will likely not matter at all.

The days where the rear gear ratio had to be deep to make up for the lack of granny type gearing to get going in automatics is long gone, and there are now multiple overdrive gears. To put it in perspective, the starting gearing on a pre -8 SPeed Ram and 3.92 gears is still not as deep as a 8 Speed equipped Ram and 3.21 gearing... (Though larger tires may eat some of this up).

I'd test drive both and decide what I liked - or if it matters at all...
 
https://www.ramforumz.com/threads/3-55s-vs-3-92s-with-8-spd.146873/
[Linked Image]

I'm very surprised to see the top gear ratio is the same on the 6 and 8 speed, seems crazy the 8spd is that much more fuel efficient.
3.92 puts the final drive ratio about the same as my Outback, which pushes much less air but hasn't got a whole lot of torque at 1500rpm either. I think with the 8spd there's not a whole lot of reasons to go with the 3.92 unless you are towing heavy alot. I'm pretty sure my Dad's 2018 6spd has got the 3.21 and unloaded it does 60 mph quite happily in top gear. Its not like the engine sounds terrible if it downshifts either, so I'd rather get good mileage most of the time and then have the odd downshift.
 
Last edited:
Originally Posted by IndyIan
https://www.ramforumz.com/threads/3-55s-vs-3-92s-with-8-spd.146873/
[Linked Image]

I'm very surprised to see the top gear ratio is the same on the 6 and 8 speed, seems crazy the 8spd is that much more fuel efficient.
3.92 puts the final drive ratio about the same as my Outback, which pushes much less air but hasn't got a whole lot of torque at 1500rpm either. I think with the 8spd there's not a whole lot of reasons to go with the 3.92 unless you are towing heavy alot. I'm pretty sure my Dad's 2018 6spd has got the 3.21 and unloaded it does 60 mph quite happily in top gear. Its not like the engine sounds terrible if it downshifts either, so I'd rather get good mileage most of the time and then have the odd downshift.


Thank you Indylan. Now let's be honest. How many of you were automatically making up opinions not realizing the truck has a .667 overdrive gear ratio. 3.92 x .667 = 2.61.
Both these transmissions have two overdrive gears. It's not your Daddy's ram with a 1 to 1 ratio in top gear with a 4:11 rear end. Get the 3.92 if you tow and the 3.55 if you don't. When you tow, you will manually select a lower gear to match your conditions.
laugh.gif
 
Last edited:
Originally Posted by The Critic
I am in the market for a new Ram 1500 and I have to make on the gear ratio. Most commonly, the choices is 3.21 or 3.92.

I have no immediate plans to do any towing. The engine will either be the 5.7L V8 or the 3.0L Ecodiesel.

For my application, does the gear ratio even matter?



No immediate plans, but if you ever have to tow, then 3.92 is choice.

To put it bluntly, 3.21 sucks. The .5 MPG you save does not justify the driveability compromise for truck duty. Whether that's towing or a quick off road romp to pull your son's Jeep out of the mud. Lower gears will make tough jobs easier on your drivetrain and make you happier scooting around town.
My $.02
 
Which trim package Ram 1500 do you plan on buying? I believe everyone I know with a late model Ram 1500, hemi, ZF8 4x4 has the 3.21 gears. This is in everything from express models to bighorns. I'm sure you can get 3.92s with various higher level trim packages, but I've only seen it in a sport model my brother was looking at a year or two back.

I know the pentastar powered versions can be had with 3.55's as my brother's 2019 Ram 1500 classic has it because he wanted the higher tow rating the 3.55's offer. Other than that, comparing my pentastar with 3.21's to his with 3.55's you can't feel a difference at all.

I would imagine you can feel, hear and see the difference between 3.21 and 3.92. Maybe even smell it, considering the tires. LOL
 
Last edited:
Originally Posted by JTK
Which trim package Ram 1500 do you plan on buying? I believe everyone I know with a late model Ram 1500, hemi, ZF8 4x4 has the 3.21 gears. This is in everything from express models to bighorns. I'm sure you can get 3.92s with various higher level trim packages, but I've only seen it in a sport model my brother was looking at a year or two back.

I know the pentastar powered versions can be had with 3.55's as my brother's 2019 Ram 1500 classic has it because he wanted the higher tow rating the 3.55's offer. Other than that, comparing my pentastar with 3.21's to his with 3.55's you can't feel a difference at all.

I would imagine you can feel, hear and see the difference between 3.21 and 3.92. Maybe even smell it, considering the tires. LOL


3.21+hemi has no problems at all making some smoke
lol.gif

[Linked Image]
 
  • Like
Reactions: JTK
Originally Posted by JTK
Which trim package Ram 1500 do you plan on buying? I believe everyone I know with a late model Ram 1500, hemi, ZF8 4x4 has the 3.21 gears. This is in everything from express models to bighorns. I'm sure you can get 3.92s with various higher level trim packages, but I've only seen it in a sport model my brother was looking at a year or two back.

I know the pentastar powered versions can be had with 3.55's as my brother's 2019 Ram 1500 classic has it because he wanted the higher tow rating the 3.55's offer. Other than that, comparing my pentastar with 3.21's to his with 3.55's you can't feel a difference at all.

I would imagine you can feel, hear and see the difference between 3.21 and 3.92. Maybe even smell it, considering the tires. LOL

Most likely, Bighorn with the Level 2 Equipment Group.
 
I don't think it makes any difference in your case. I enjoy the 3.92's in my 16 with the hemi. Towed a decent sized pontoon a couple weeks ago, maybe 3500lbs but a big wind drag, and my truck only got down to 6th on the biggest hills running 65mph. Stayed in 8 most of the time and 7 took care of most of the smaller hills. I was really impressed. I will tell you that I've never cracked 20mpg on the highway. It'll get close but I've never made it..
 
Last edited:
You must log in or register to reply here.

Similar threads

F
Help me to understand towing capacity
2
Replies
39
Views
2K
MrHorspwer
OVERKILL
RAM 1500 DT vs DS warm-up time... wow
2 3
Replies
46
Views
3K
OVERKILL
N
2016 Ram 1500 Hemi towing impressions
Replies
9
Views
1K
ekrampitzjr
F
Towing Comparison 2018 Ford F-150 w/ 3.3L 6R80 3.73 vs. 2014 Ram 1500 3.6L 8SPD 3.21
Replies
11
Views
2K
meep
92saturnsl2
2006 Dodge Ram 1500 4WD ball joint replacement
Replies
1
Views
475
RAR
Back
Top