3.21 vs 3.92: The Last Word

[Ninety-9 SE-L]

I think this topic is a bit beaten to death.

Personally, I think the 3.21 is fine for most scenarios, including towing. The only determining factor is if you plan to tow a lot on inclines. The difference between the 3.21 and 3.92 disappears at 24mph. In fact if you did a rolling drag race at 25MPH, I'd bet the 3.21 would win because @25mph, the 3.21 is still at the top of 1st, the 3.92 has advanced to 2nd (lower G/R), and all of the gearing is the similar, thereafter, with the 3.21 always 1 gear down.

Tow-wise, we're talking about the same truck with the same engine/trans, same suspension, same brakes, same sway control, same size, same weight distribution, and so on. To me, tow capacity isn't about power, it's about suspension and brakes. I take capacities with a grain of salt because a properly loaded/hitched trailer is always the bigger factor than how much it weighs.

The 3.21/3.92 axle is such a minor change on an otherwise IDENTICAL truck. The only difference you'll feel is between 0 and 24mph. If you maintain more than 24mph, there is NO difference, even on hills because after 24mph, the final drive ratio is exactly the same (with the 3.21 being one gear lower). The only reason the 3.92 will be a necessity is if you tow up/down low-speed mountain roads. If you're going to be starting/stopping on steep hills or doing low-speed pulls, the 3.92 will certainly be crucial.

 

[SnowBlaZR2]

The only reason the 3.92 will be a necessity is if you tow up/down low-speed mountain roads. If you're going to be starting/stopping on steep hills or doing low-speed pulls, the 3.92 will certainly be crucial.

The discussion isn't about necessity. Never has been. I could pull my current camper with a mid-sized SUV if I felt like wearing it down and waiting a week for it to accelerate.

I don't know or care how anyone else tows, but I spend a lot of time away from the highway with my camper behind me. 3.21s would work. 3.92s just work better.

 

[djevox]

Is this the forum version of Clickbait?

 

[SnowBlaZR2]

Is this the forum version of Clickbait?

I always think "free beer and pizza" when I see one. I keep expecting someone to tell me I get to help them move when I reply.

 

[TNRamGuy]

isn't about necessity.

Hell it's not even about logic and barely about sanity at this point!
That said I do get a laugh out of it

 

[Mountain Whiskey]

The discussion isn't about necessity. Never has been. I could pull my current camper with a mid-sized SUV if I felt like wearing it down and waiting a week for it to accelerate.

I don't know or care how anyone else tows, but I spend a lot of time away from the highway with my camper behind me. 3.21s would work. 3.92s just work better.

Yea, even without a camper or trailer, I just think the 3.21 guys either like pissing off everyone else in traffic, slowing down the Honda Fit drivers that are winging around them or are just embarrassed by the poor choice and don't want to admit it.

 

[Mirowpl]

This is what comes to mind when reading the older thread in this topic and now this new one

 

[theblet]

3.21 seconds to 60mph is faster than 3.92 seconds so there’s your winner

 

[Ramroo]

Yea, even without a camper or trailer, I just think the 3.21 guys either like pissing off everyone else in traffic, slowing down the Honda Fit drivers that are winging around them or are just embarrassed by the poor choice and don't want to admit it.

SnowBlaZR2 did bring up a thought. The SUV thing. I could see y’all in a KIA Soul or later model Nissan Cube. Just consider it. Nobody would ever suspect you of runnin liquor in a cube.

 

[SnowBlaZR2]

SnowBlaZR2 did bring up a thought. The SUV thing. I could see y’all in a KIA Soul or later model Nissan Cube. Just consider it. Nobody would ever suspect you of runnin liquor in a cube.

 

[SnowBlaZR2]

This is what comes to mind when reading the older thread in this topic and now this new one

View attachment 129585

I knew you had 3.21s before I even looked.

 

[Ninety-9 SE-L]

The discussion isn't about necessity. Never has been. I could pull my current camper with a mid-sized SUV if I felt like wearing it down and waiting a week for it to accelerate.

I don't know or care how anyone else tows, but I spend a lot of time away from the highway with my camper behind me. 3.21s would work. 3.92s just work better.

But could that mid-sized SUV stop that camper from 70mph or deal with sway or tongue weight?

My main argument is that at the end of the day, the only difference between my truck with a 3.21 and 3.92 is....well that. I'm still pulling with a 1500 Diesel RWD Laramie, which is otherwise rated to tow 10,000lbs. One single component just ate up 1800lbs of my capacity, and the only major thing it affects is my acceleration from 0-24mph. That's why I say that I'm not really that worried if I suddenly needed to pull 10,000lb, one day. I'm still going to be able to carry the weight and stop the same.

Throwing a mid-size SUV into the equation changes pretty much everything about this argument, you'd probably be riding on the bump stops, or worse, in a ditch because you couldn't stop.

 

[Mountain Whiskey]

SnowBlaZR2 did bring up a thought. The SUV thing. I could see y’all in a KIA Soul or later model Nissan Cube. Just consider it. Nobody would ever suspect you of runnin liquor in a cube.

That's what the ol' Town Car is for. Air bags in the rear self level it while heavy sway bars and shocks let it take the corners and remain stable. Throw a box of tissues in the back window and who would suspect?

 

[SnowBlaZR2]

But could that mid-sized SUV stop that camper from 70mph or deal with sway or tongue weight?

Yes.

My main argument is that at the end of the day, the only difference between my truck with a 3.21 and 3.92 is....well that.

I get that, but it's not accurate. If there wasn't any difference we'd have one gear ratio.

I'm still pulling with a 1500 Diesel RWD Laramie, which is otherwise rated to tow 10,000lbs. One single component just ate up 1800lbs of my capacity, and the only major thing it affects is my acceleration from 0-24mph. That's why I say that I'm not really that worried if I suddenly needed to pull 10,000lb, one day. I'm still going to be able to carry the weight and stop the same.

Towing involves more than cruising the highway and stopping for gas. You can tow 10k, but it's going to be harder on your powertrain than it is on mine. That's why you have a lower rating.

Throwing a mid-size SUV into the equation changes pretty much everything about this argument, you'd probably be riding on the bump stops, or worse, in a ditch because you couldn't stop.

A lot of them have tow ratings of 5k lbs. That should easily handle a decent sized camper, and hell, apparently I could bump that up to 8k if I wanted. It has brakes and suspension and stuff.

 

[Ninety-9 SE-L]

Yes.
I get that, but it's not accurate. If there wasn't any difference we'd have one gear ratio.
Towing involves more than cruising the highway and stopping for gas. You can tow 10k, but it's going to be harder on your powertrain than it is on mine. That's why you have a lower rating.
A lot of them have tow ratings of 5k lbs. That should easily handle a decent sized camper, and hell, apparently I could bump that up to 8k if I wanted. It has brakes and suspension and stuff.

I should have been more specific. Most CUV/SUVs can handle about 5k. Our trucks can handle 9-10k, on average. The main reason for that is our frame, tires, brakes, length/width, power, and gearing. Sure, an SUV could handle some small campers, but nothing major and certainly not to our trucks' limits. Apples to oranges. The 3.21/3.92 argument isn't even close to comparing a 1500 to a midsize SUV. Trust me, I tried looking before I settled on another pickup truck.

For powertrain strain, the 3.92 has a higher reduction to produce more wheel torque. It's easy to think that because there's a smaller multiplier than more torque has to come off of the AT's output shaft to produce the same power. That's not exactly true. I can't make the engine/transmission produce more or less power/torque just by changing the rear end. I'm simply giving myself a mechanical advantage at the wheels. At 100% throttle, the transmission is going to output the same amount of power/torque regardless of what's down the line. At continuous cruising speed, I may have more torque coming off the transmission in order to make up for the 15-20% loss in rear-wheel torque, but that doesn't concern me because I'll only be operating at partial throttle.

It also doesn't concern me because I have RWD and no plans to **** with the wheels/power train. A lot of ya'll own 4x4s and have increased your tire diameters. Are you guys having problems with the A/T, heat, or reliability? Didn't think so. Putting on bigger diameter tires reverses some of the advantage in the 3.92. Transfer case, 2 prop shafts, 2 diffs, 4 axle shafts, hmmm, that could put more strain and drivetrain loss on your transmission. That sounds a lot harder on your powertrain than simply having a longer(shorter?) final drive.

I'm not claiming to know better than the Engineers that rate our trucks, but I know that many of these DOT tow ratings exist in order to weed out the least common denominator, like this guy:


If I was making a lot of pulls up mountain passes or I needed a lower crawling gear, I'd definitely think twice about having a 3.21. But I think a lot of you put way too much praise into the 3.92, and maybe it's because a lot of you do things that require a crawling gear, or it's because most of you have 4x4s and large-diameter tires that adversely affect your acceleration.

I've only been on here a short while, but I can see this discussion comes up a lot. Ya'll really put way too much belief into the 3.92 while passing the 3.21 off as trash. Especially when you can drop down a gear and basically have all the same final drive ratios (except 1 and 8). The 3.21 has its limits, but honestly, I wouldn't think twice about putting 10k on the back of my truck in all but the most strenuous circumstances, which will probably never be a problem because I don't live in the mountains.

 

[ferraiolo1]

They are just living in the world of th400 transmissions. Now that we have 8-10 speed transmissions, different rear gear ratios really don’t have as much of an affect as they used to. Unless of course if you’re talking about mpg. Than 3.21>3.92


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[SnowBlaZR2]

I should have been more specific. Most CUV/SUVs can handle about 5k. Our trucks can handle 9-10k, on average. The main reason for that is our frame, tires, brakes, length/width, power, and gearing. Sure, an SUV could handle some small campers, but nothing major and certainly not to our trucks' limits. Apples to oranges. The 3.21/3.92 argument isn't even close to comparing a 1500 to a midsize SUV. Trust me, I tried looking before I settled on another pickup truck.

It's not apples to oranges. We're talking about exceeding the capabilities of a vehicle. I'm just willing to go a little further when I ignore the limitations. Your truck has a rated towing capacity for a reason, whether you agree with it or not. It's not "just because," it's because your truck is less capable than my truck. So is a midsize SUV. So is a minivan.

For powertrain strain, the 3.92 has a higher reduction to produce more wheel torque. It's easy to think that because there's a smaller multiplier than more torque has to come off of the AT's output shaft to produce the same power. That's not exactly true. I can't make the engine/transmission produce more or less power/torque just by changing the rear end. I'm simply giving myself a mechanical advantage at the wheels. At 100% throttle, the transmission is going to output the same amount of power/torque regardless of what's down the line. At continuous cruising speed, I may have more torque coming off the transmission in order to make up for the 15-20% loss in rear-wheel torque, but that doesn't concern me because I'll only be operating at partial throttle.

A mechanical advantage means less power is needed to accomplish the same work.

It also doesn't concern me because I have RWD and no plans to **** with the wheels/power train. A lot of ya'll own 4x4s and have increased your tire diameters. Are you guys having problems with the A/T, heat, or reliability? Didn't think so. Putting on bigger diameter tires reverses some of the advantage in the 3.92. Transfer case, 2 prop shafts, 2 diffs, 4 axle shafts, hmmm, that could put more strain and drivetrain loss on your transmission. That sounds a lot harder on your powertrain than simply having a longer(shorter?) final drive.

I have the stock tires on my truck, and would only change them for the exact size with a better load rating.

If you have to keep adding qualifiers on top of qualifiers to make the 3.21s seem better than they are...well, is that really what you're doing?

I'm not claiming to know better than the Engineers that rate our trucks, but I know that many of these DOT tow ratings exist in order to weed out the least common denominator, like this guy:
View attachment 129646

OK, but if you can exceed DOT tow ratings, so could someone with 3.92s. And you're exactly where you started.

If I was making a lot of pulls up mountain passes or I needed a lower crawling gear, I'd definitely think twice about having a 3.21. But I think a lot of you put way too much praise into the 3.92, and maybe it's because a lot of you do things that require a crawling gear, or it's because most of you have 4x4s and large-diameter tires that adversely affect your acceleration.

I've only been on here a short while, but I can see this discussion comes up a lot. Ya'll really put way too much belief into the 3.92 while passing the 3.21 off as trash. Especially when you can drop down a gear and basically have all the same final drive ratios (except 1 and 8). The 3.21 has its limits, but honestly, I wouldn't think twice about putting 10k on the back of my truck in all but the most strenuous circumstances, which will probably never be a problem because I don't live in the mountains.

I don't remember the last time I saw a thread that was started for any reason other than to explain away why 3.21s aren't mostly useless after all, including the one you're in now. They aren't trash, but you do have a better option if you didn't just buy whatever you could find on the lot.

 

[ferraiolo1]

My dealer lot had both. I knew what I chose, and why I did it.

I just stay in a hotel vs carrying a large portable toilet behind me for vacations


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[djevox]

My dealer lot had both. I knew what I chose, and why I did it.

I just stay in a hotel vs carrying a large portable toilet behind me for vacations


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[SnowBlaZR2]

My dealer lot had both. I knew what I chose, and why I did it.

Right. You're a true believer.

I just stay in a hotel vs carrying a large portable toilet behind me for vacations


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Sleeping in a public bathroom with a bed in it isn't my idea of a vacation, but I'm not a homeless person, either.