3.73 and 4.10 gearing Q&A

Jomax · Jun 27, 2015

I tow 17k with 37s and 3.55. I honestly don't feel the need for bigger gears. I love the way it drives.

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CMCx2012 · Jun 28, 2015

10-4!

dseitler · Jun 28, 2015

Jomax said:
I tow 17k with 37s and 3.55. I honestly don't feel the need for bigger gears. I love the way it drives.

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Same here. Been running a Non-VGT Turbo setup with 3:55 Gears for a couple of years now. Have 15,000 miles towing 17,000Lbs or more with no problem on 32" tall tires. Turbo spools with absolutely no problem and tow's with easy. No plans ever on doing a gear change.. I recommend changing your transmission tune long before a gear change.

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Morgan@Midwest Diesel & Auto · Jun 28, 2015

torque beast said:
I am the same set up. I am lifted 4.5" with Toyo MT 35" tires and can pull my tractor at 75 mph on the interstate with no issues. The low geared transmission helps a lot to get going and once moving there is plenty of hp. The only way I would gear down is if I was pulling heavy. You can actually hurt your 1/4 mile time by gearing too low

When I ditched the 3.31's for 3.73's my 1/4 mile improved. The 3.31's and 2nd gear launch were just too much to pull through. Wish I did 4.10's

CMCx2012 said:
So basically the 4.10's would scream at highway speeds or does that only apply to my old Mustang GT that had them, lol.

The consensus is that the 3.73 with 35's wont be more of a benefit over the factory 3.55 gearing, am I right?

If you are not towing and not running a larger non vgt it will work fine. I had a s366 on my ccsb with 35's/3.55's and it worked fine. I even towed fairly heavy 25k or so. Just couldn't tow heavy and use 6th or it would downshift too much.

For anyone one who is anal about what they drive, you will not regret the gear swap. Mine feels much more effortless when taking of and city driving and even with 33's the 3.73's. It cruises at 80mph on the interstate just fine.

If your not really that worried about your combo being absolutely perfect it is fine because these transmissions are awesome at making up for steeper rear end gears in most situations.

35's and 3.73's or 37's and 4.10's it's hard to go wrong with either of those combos.

And for a truck wanting to go fast, the 3.73's with a set of 32.5-33" nitto 420's is an absolute riot.

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RedRice589 · Jun 28, 2015

Morgan@Midwest Diesel & Auto said:
When I ditched the 3.31's for 3.73's my 1/4 mile improved. The 3.31's and 2nd gear launch were just too much to pull through. Wish I did 4.10's

If you are not towing and not running a larger non vgt it will work fine. I had a s366 on my ccsb with 35's/3.55's and it worked fine. I even towed fairly heavy 25k or so. Just couldn't tow heavy and use 6th or it would downshift too much.

For anyone one who is anal about what they drive, you will not regret the gear swap. Mine feels much more effortless when taking of and city driving and even with 33's the 3.73's. It cruises at 80mph on the interstate just fine.

If your not really that worried about your combo being absolutely perfect it is fine because these transmissions are awesome at making up for steeper rear end gears in most situations.

35's and 3.73's or 37's and 4.10's it's hard to go wrong with either of those combos.

And for a truck wanting to go fast, the 3.73's with a set of 32.5-33" nitto 420's is an absolute riot.

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I have to agree my truck spends the majority of it's time hooked up and it's to 8-18k and I hated the 35'" toyos and 3.55s on stock turbo, when I swapped to a 15 turbo it was better but the motor was always lugging mileage was still poor. Now with 4.30s and tiny little stock tires on my 15 dually which is bone stock I get the same 10mpg running the same speed as my 12. Personally I felt I needed to do a gear swap as my 6.4 srw 350 had 4.10s and a 35" tire as well it was much nicer. But if I wasn't towing it never would come up. Truck drove great but it's the little thing you notice when you watch small variables change. Like stock tires to 35" mts, not deleted to deleted, then a 15 turbo then an intake all of it changed and contributed to the rise and fall.

torque beast · Jun 29, 2015

Morgan@Midwest Diesel & Auto said:
When I ditched the 3.31's for 3.73's my 1/4 mile improved. The 3.31's and 2nd gear launch were just too much to pull through. Wish I did 4.10's

I have not done a swap in these trucks so those of you that have will know more than me. I was just stating in general. For example, I took a 454ss pickup and changed from 3:73 to 3:23 and the 1/4 mile improved because it had the power to move it. I know it is apples and oranges comparing the two but like you said starting off in second changes everything.

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CMCx2012 · Jun 29, 2015

Thanks to everyone here for contributing! Lots of great intel and knowledge for those who wish to do the swap.

CMCx2012 · Jun 30, 2015

I am putting the idea of a gear swap way up on the shelf for now. We can keep up the talk and experience here, but to me the more important (and most logical) worry right now is the completion of my project under the hood and the suspension installation.

After it is all said and done, then I will worry about the gear situation. (If I even need them)

BOHICA256 · Aug 24, 2015

Morgan@Midwest Diesel & Auto said:
When I ditched the 3.31's for 3.73's my 1/4 mile improved. The 3.31's and 2nd gear launch were just too much to pull through. Wish I did 4.10's

If you are not towing and not running a larger non vgt it will work fine. I had a s366 on my ccsb with 35's/3.55's and it worked fine. I even towed fairly heavy 25k or so. Just couldn't tow heavy and use 6th or it would downshift too much.

For anyone one who is anal about what they drive, you will not regret the gear swap. Mine feels much more effortless when taking of and city driving and even with 33's the 3.73's. It cruises at 80mph on the interstate just fine.

And for a truck wanting to go fast, the 3.73's with a set of 32.5-33" nitto 420's is an absolute riot.

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I have 3.31s and 33s, truck is 2wd and im possibly wanting to go to 3.73, I have the S367.7 and I've been doing 1000 miles a week for the past 2 months, 80-85% highway. So my truck is always on the highway.
Tows a small handful as of now. So my truck is empty 90% of the time. Should start towing quite a bit more next year though.

Wanting opinions and especially the opinions from people that have gone from 3.31 to 3.73 before I pull the trigger.

throttlejocky316 · Aug 24, 2015

I thought my gearing was perfect with 3.55's and 35's. I cruised at 1700 rpm at 70 mph. I have since switched to 37's and my rpms are barely over 1500. This causes down shifts on the slightest hills, not bad just annoying. I am looking at doing a streetmax turbo upgrade. How will this turbo react compared to the stock one from such a low rpm? I have considered going to 4:10 gears but 3:73 would put me back to stock ratio that I had with 35's.

bigrpowr · Aug 24, 2015

throttlejocky316 said:
I thought my gearing was perfect with 3.55's and 35's. I cruised at 1700 rpm at 70 mph. I have since switched to 37's and my rpms are barely over 1500. This causes down shifts on the slightest hills, not bad just annoying. I am looking at doing a streetmax turbo upgrade. How will this turbo react compared to the stock one from such a low rpm? I have considered going to 4:10 gears but 3:73 would put me back to stock ratio that I had with 35's.

go to 3:73 with 35's , 4:10's or 4:30's with 37's . i went with 3:73 just in case i went back to stock , as 4:10 is a good bit tall for 33's .