3.21 vs 3.92

[bryan28]

Today while my truck was at the dealership for service I had the opportunity to drive a Laramie crew cab 4x4 hemi with 3.92 rear diff. My quad cab 4x4 hemi has the 3.21s. I can now speak from experience when I say the difterence between the two as far as off the line acceleration and roll on acceleration are concerned is minimal. The Laramie did feel a little peppier but not what I'd expected. If I buy another Ram in the future it will have the 3.92 solely for the fact that it is rated to tow more but it won't leave the 3.21 in its dust as some here might claim.

 

[SitKneelBend]

Blasphemer!

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[Hemi450hp]

The Laramie Crew is heavier than your Sport Quad, so that will slow the Laramie down. Try to drive another sport quad with the 3.92's and the difference will be even more noticeable.

 

[bryan28]

Yeah I looked for a quad with the 3.92s but i was lucky to find a crew. They don't get many with 3.92 on their lot for some reason.

 

[bryan28]

Just looked on the Ram site and unless it's a typo the quad sport 4x4 has a base curb weight of 5426 lbs and the crew Laramie 4x4 has a base curb weight of 5326 lbs. Not sure if it's because of the longer bed on the quad but that's what the site says. The site also says the Laramie quad 4x4 weighs even less with a base curb weight of 5273 lbs.

 

[SitKneelBend]

Are you sure the loaner wasn't a 3.6L?[emoji6]

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[bryan28]

What is the base engine in the Laramie? Maybe the weight difference is in the v6 if it's standard. The truck i drove had a hemi.

 

[bryan28]

Yes I am positive the loaner had the hemi. Can't find any specs on the difference in weight between the v6 and hemi but it can't be that much. I stand by my assessment that the 3.92 doesn't have much on the 3.21 in acceleration. I just looked up the exact truck I drove and it has the hemi and weighs in at 5556 lbs as configured. Only 130 lbs more than mine if all numbers on the ram site are correct.

 

[Kotta390]

The 3.92 vs 3.21 debate is not nearly as a noticeable difference with the 8HP70 transmissions as it is between the 65RFE transmssions. Don't get me wrong, I wouldn't mind having a 3.92 gear set, but after driving my friends 2014 R/T truck, it is barely noticeable on the acceleration difference. His shifts more often then mine so there are times where his truck feels luggish at certain speeds where mine doesn't. We haven't gotten to run them yet, but when we do Ill post results. I have muffler and catch can and he has a muffler and drop in filter, soon to get catch can. So it should be relatively close match up. I just love his 8.4 radio! <3

 

[mhb1638]

Not to add any fuel to this discussion, but I have literally owned quite a few rams, sadly. 2011,2012,2013,and two 2015s. The 13 and previous 15 were Cc sports with 3.21. My current 15 has 3.92 gears. It's also a bighorn anD 4x4. Not sure the 4x4 changes much. But this truck is very quick off the line compared to any previous ram. The gears pull hard. It's much quicker than my 3.21 geared trucks. But at same rate, the previous 3.21 geared trucks would own me on the interstate. And previous trucks did better in gas. But this one is indeed quicker. Just my thoughts

 

[THETANK]

Had a 14 Sport rcsb 4x4 with 3:21's now the 15 R/T with the 3:92's. As mentioned in the past I find neither vehicle particularly quick/fast but theta's just me.

 

[smurfs_of_war]

Put some weight on them, then try. I suspect the difference may be a bit more noticeable. Not huge by any means, but noticeable.

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[7777xm]

I noticed a difference between 3:55s & 3:92s. I can't imagine 3:21s.



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[Ricks Ram]

I noticed a difference between 3:55s & 3:92s. I can't imagine 3:21s.



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Yea I'm kinda thinking the same thing. 3:21 to 3:92 is a big difference. I have the 3:92 8 speed and I easily noticed the difference when I test drove both 3:21 and the 3:92. It's almost 3/4 of a turn rotation of the drive shaft per one revolution of the wheel which is substantial. I have been racing for years and I have gained almost a 1/2 a second in the quarter by making a 4:11 to 4:56 gear change.

 

[bryan28]

7777xm was the 3.55 in a 6 speed? I've been told by a member with 3.92/6 speed that the 3.21/8 speed is a much better choice because of the transmission. But I'm just going by what it felt like to me. No actual timed runs or anything. I am by no means an expert.

 

[7777xm]

7777xm was the 3.55 in a 6 speed? I've been told by a member with 3.92/6 speed that the 3.21/8 speed is a much better choice because of the transmission. But I'm just going by what it felt like to me. No actual timed runs or anything. I am by no means an expert.

I owned two 2010s, one had the 3:55 and the other had the 3:92. That was a noticable difference.

I test drove a lot of 2013s and 14s. The 8 speed helps a lot with the 3:21 but straight up acceleration, the 3:92s walk all over the other. The 3:21 is good for the better highway MPG, but you lose towing weight with the 3:21. I found the 3:92 rear will hold 8th much better on hills then the 3:21 did.

It all depends on what you are looking to get out of it.

If you're a mild driver, both setups will feel about the same.


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[clh1220]

Yea I'm kinda thinking the same thing. 3:21 to 3:92 is a big difference. I have the 3:92 8 speed and I easily noticed the difference when I test drove both 3:21 and the 3:92. It's almost 3/4 of a turn rotation of the drive shaft per one revolution of the wheel which is substantial. I have been racing for years and I have gained almost a 1/2 a second in the quarter by making a 4:11 to 4:56 gear

But what transmission did you have with those gears. The 8 speed makes a big difference. It's damn sure is not like the old days, with a turbo 350 or 400 3 speed.

 

[Ricks Ram]

Yea I'm kinda thinking the same thing. 3:21 to 3:92 is a big difference. I have the 3:92 8 speed and I easily noticed the difference when I test drove both 3:21 and the 3:92. It's almost 3/4 of a turn rotation of the drive shaft per one revolution of the wheel which is substantial. I have been racing for years and I have gained almost a 1/2 a second in the quarter by making a 4:11 to 4:56 gear

But what transmission did you have with those gears. The 8 speed makes a big difference. It's damn sure is not like the old days, with a turbo 350 or 400 3 speed.

The transmission was a modified C6 in a Torino that I still have but I don't race it as much as I used to. I have other cars I am playing with now. I understand that the 8 speed transmission makes a huge difference and as stated the 3:21 8 speed is no slouch and obviously the more gears you have the better the truck will accelerate but gear ratio still comes into play and the 3:92 gear ratio was a noticeable difference on the trucks I drove.

 

[68Malibu383]

It should be pretty noticeable but tire size would also affect this. If the 3.92 truck had taller tires, it will "cancel" out the lower gearing advantage.