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Discussion Starter #1
I have been kicking around a newer truck. Found one i really like, Platnum Fx4, but has 3.31 gears. I plan to pu my Raptor Rims/ 35" tires on it.

Anybody tuned run the 3.31's? Any trouble running in 10th on the highway with taller tires? I'm not sure how much it matters with the speed. I see tow ratings between the 3.31 and 3.55 are negligible.

Hoping to get some feed back to ease my mind.
 

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So I recently traded a 2018 5.0 with 3.31 gears for a new 2020 3.5 with 3.55 gears and I will never get another truck with the 3.31 gears. My old truck was leveled with 33's and would have a hard time holding 10th unless it was completely flat. It was also an absolute dog while towing which was the primary reason I traded.

I have swapped my 33's onto the new 2020 but its not leveled just yet and it has absolutely no issues holding 10th at 55 MPH. I know the difference in the 5.0 vs the 3.5 isn't really comparing apples to apples but in my experience having 3.31 gears with larger tires is a no go.

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I'd argue something was wrong with your previous truck. Mine is a 2013 w/3.31 gears and has zero problem holding gears on any hill.
The tow ratings ARE negligible.
 

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Why do you want to "hold 10th", especially with 3:31?

It's the 3rd overdrive ratio. It's OK to have it if you are FLYING, of course.

And yea, you can't really make an apples/apples comparison between differential ratios if you change the whole motor too.

Grab one of these new muscle cars with the 10-speed and check out if at 70 or even 80 if it neeeeds to be in 10th. Again, remember, there's 3 overdrive ratios.

We have 3 2018 3.5's in our family fleet. One is the HDPP and another is still a 3:55, and the only tuned one is the 3:31 with 35's.

Wanna know which one absolutely will out-scoot the others? Or you could say that dang if it doesn't have the power to PULL that taller gear!

Seriously, the 10-speed is kind of the equalizer for the old argument for differential ratios. Especially when you are talking about these torque monster motors.



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Discussion Starter #5
so does your 18 with 3.31 and 35's hold 10th at 70?
 

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I'd argue something was wrong with your previous truck. Mine is a 2013 w/3.31 gears and has zero problem holding gears on any hill.
The tow ratings ARE negligible.
Yeah, the problem was it was a 5.0 and had no low end grunt. With a 5.0 I would look at at least 3.55's if not 3.73's. Especially if I planned on taller tires.

But also, his 10 speed 2018 has a significantly taller 10th gear than your 6 speed. like 20% taller. The truck has to drop to 9th to be equal to your 6th.
 
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so does your 18 with 3.31 and 35's hold 10th at 70?
Just remember, 9th gear is the same ratio as the 6th in your current 6 speed. So even if you downshifted to 9th, you're still at a taller overall ratio than your 6 speed/3.73 setup. 8th puts you slightly shorter than your current 6th gear.

Oh and 1st gear in the 10 speed with 3.31's is almost the exact same ratio as your current first gear with 3.73's, so off the line performance will be at least as good.

So unless you simply don't want it shifting, its not like you are lacking ratios or the trucks not gunna be able to find a happy place.
 
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Yeah, the problem was it was a 5.0 and had no low end grunt.

But also, his 10 speed 2018 has a significantly taller 10th gear than your 6 speed. like 20% taller. The truck has to drop to 9th to be equal to your 6th.
I was gonna say this. All other things equal, an eco 3.31 is going to run circles around a 5.0 3.31. Especially with big tires.

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so does your 18 with 3.31 and 35's hold 10th at 70?
I don't know how fast I would have to be going to get my truck to shift to 10th gear.

I drive my truck in 10-speed mode, (Sport) and at 75mph it is still in 8th gear. That's with 34.8" tires programmed into the computer and within 1mph of GPS. Also, just the tiniest amount below 2000rpms indicated.

So to cruise in 10th would likely get me in trouble with The Man! Even here in Texas. Lol

I have seen my truck in 10th, of course. Many probably have when they use "Normal" mode.
I'm just not a fan of it.

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Discussion Starter #10
so yours wont cruise at 60-70 mph in 10th gear? at 1400 rpms?
 

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Dang, 10th at 60?

I don't know. But I hope not. Would that be a good thing for the drivetrain? And even if it was in 10th at 60, even the tiniest request for additional power would have it shifting down, and for good reason, no?

I think I'm missing something in the conversation.



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Discussion Starter #12
I guess my point is why the 3.55 would be better with the taller tires. Gives you more range in all the gears, 10th still being and option for cruising. I mean the 10 speed and 3.31 will still be better than my current 6 speed and 3.73, but not as good as a 10 speed 3.55. I mean really me putting 35's on a 10speed and 3.55 will make it like stock tires and a 3.31 right. using round numbers.
 

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I certainly wouldn't argue AGAINST 3:55
Or even 3:73 for that matter.

I think all that I'm (and others) saying is that with the 10r80 and the mighty 3.5 Ecoboost, the issue just simply isn't what it used to be. But having said that, I guess I'm just confused why you WANT to use 10th gear so determinely? Especially at relatively low speed.

It's nice to have 10th, of course. It's a very modern feature. Afterall, there ARE stretches of 85mph highways these days and that 3rd overdrive is perfect for caroooooozing at 5-over, if you know what I mean.

Our dads and grandads trucks couldn't possibly deliver the quiet, comfortable, luxurious and relaxed experience at 90mph that our latest 10r80 3.5 Ecoboost trucks can. It's really amazing when you think about it.

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Discussion Starter #14
ya, it just seem usless to have a 10 speed and such "high" rear gearing is my point. and coupling that with taller tires just seems more like a waste. I understand the 3.5 can do it. just not sure i want to settle for the 3.31. lol im pretty particular. Im not sure if i should keep modding my gen 1 or just bite the bullet on a gen 2.
 

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ya, it just seem usless to have a 10 speed and such "high" rear gearing is my point. and coupling that with taller tires just seems more like a waste. I understand the 3.5 can do it. just not sure i want to settle for the 3.31. lol im pretty particular. Im not sure if i should keep modding my gen 1 or just bite the bullet on a gen 2.
Well, that comes close to the age old argument made that "why do you neeeeed 600HP? Or 500? Or even 300, since it wasn't that long ago that 300 was only found in a fraction of" high performance" cars.

I just saw the latest Throttle House video that was a showdown between the latest 4 cylinder Turbo cars. It's kind of funny since one of the fastest cars is none other than the Honda Accord.

And it too has a 10-speed transmission.




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so does your 18 with 3.31 and 35's hold 10th at 70?
It only did while on a flat road. Any incline and it would downshift to 7 or 8. As was already mentioned a large part of that was likely the 5.0 needing to rev far higher than the 3.5 for torque but the 3.31 gears coupled with the 33" tires certainly didn't help. FWIW I did put the stock wheels and tires back on before trading the 2018 and it would shift into 10th and hold it much longer than the heavier 33's.
 

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Discussion Starter #18
I thought you were getting turbos? lol
Thats the rub. do i spend another 2k on this thing, or do i just bite the bullet on a newer truck that has the turbos on it already. Obviously other benifits to a newer truck. But i do have this truck the way i want it for the most part.
 

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Thats the rub. do i spend another 2k on this thing, or do i just bite the bullet on a newer truck that has the turbos on it already. Obviously other benifits to a newer truck. But i do have this truck the way i want it for the most part.
I am right there with you. But you are already so far in, you've already got the supporting mods done. You're not getting that back, so whats another 2k.

But I agree. Starting with a 2018+ truck makes most sense to me. Even if I took a 10-15k hit on the upgrade, I need to invest a lot of money into my 2014 truck just to get to the same power level that a tune only 2018 makes and ill still be slower because my truck weighs 6200 lbs. Right now I only have ~$1500 invested in pure performance mods as everything I have bought, except the CRP manifolds, was second hand including my SCT X4.
 

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Discussion Starter #20
Exactly.

I would probably take all the mods off except for the CRP Manifolds. I can get some money back on them. That's part hot rodding though. I do have a buddy that swears hed buy my truck now as it sits with the mods. But if i put turbos on, it may be to much for him. So there's that option to.

Hence why im trying to educate myself on options.
 
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