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How are people liking 4.09 gears in the MT82?

ash9785

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Oh sure, now they're thinking about it...I asked them and US Gear a few months ago about 4.30's and they both said forget it LOL!
I've done the math same as you, really seems like 4.30s are the sweet spot for the MT82-D4. 4.56s are just a pinch too much at 2600rpm at 73mph, 2800rpm at 78mph. It's logical to go with the 4.09s because its the best alternative and closest to the ideal ratio of 4.30, but sure would be nice for someone just to produce 4.30s.

I was exchanging emails with Gus at Yukon, I can ask him if they would be willing to set up a preorder for 4.30s on their website. I'll keep you posted.
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BmacIL

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I'm actually pretty convinced that Ford would've ended up with better EPA numbers with the old trans ratios. It's not a light econobox, it needs gear reduction. They created a more efficient engine and got the same fuel economy ratings as 15-17.
 

Black19GT

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Another curious topic. Just got a quote for the parts through local ford dealer. My car is a year round daily ‘19 MT82 non performance pack car so I have the factory 3.55’s.

Really wondering if going to 4.09’s is worth it even if it’s just in the “smiles per gallon” category? Never done rear gears before but everyone I talk to about it says they can wake the car up and make it feel a lot lighter.
 

ash9785

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Another curious topic. Just got a quote for the parts through local ford dealer. My car is a year round daily ‘19 MT82 non performance pack car so I have the factory 3.55’s.

Really wondering if going to 4.09’s is worth it even if it’s just in the “smiles per gallon” category? Never done rear gears before but everyone I talk to about it says they can wake the car up and make it feel a lot lighter.
I think it really just depends on what you're doing with the car. There are reasons for not changing the ring and pinion if you're a drag racer because you can run the 1/4 in 3rd gear with a 3.55 or 3.73. Seems like its worth it for daily driving/autocrossing if you can get the install done at a reasonable price ($300-500).

Personally I'm hardly on the highway, I almost never use 6th gear, and the closest drag strip is an hour and a half away so it makes sense to swap out rear gears to shorten everything up and generally make the car more fun to drive.
 

w3rkn

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Does anyone have one of the diagrams/calculus showing the gearing rpm to speed per gear charts...? (Looks like a saw blade)

I would need to see them side by side, before I could make a decision.
 

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Jsouthard22

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Another curious topic. Just got a quote for the parts through local ford dealer. My car is a year round daily ‘19 MT82 non performance pack car so I have the factory 3.55’s.

Really wondering if going to 4.09’s is worth it even if it’s just in the “smiles per gallon” category? Never done rear gears before but everyone I talk to about it says they can wake the car up and make it feel a lot lighter.

In terms of acceleration this gear ratio will literally make the car feel 10x quicker. But the price you pay for that will be on the highway at typical cruising speeds. In my experience I always found myself being passed by corollas because of how high the RPM's would have to be just to keep up with the flow of traffic. For example my RPM's in 6th gear would be at about 2600-2800 while cruising at 80mph. This ended up causing everthing inside the cabin to vibrate because of the straight pipe exhaust system I had. But if you dont often cruise at highway speeds, they are the #1 bang for your buck IMO. Not trying to make them sound like a negative upgrade what so ever, If my new Gt didnt come with 3.73 Performance Pack gears I would have literally ordered the 4.09's the moment I got the car home from the dealership. The best way I can explain the pull of 4.09 gears is like having an extra 150lbs of torque. Enjoy being able to have instant power at RPM's as low as 1500.
 

Mikepol2

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If you calculate force applied to the road by the rear tires and work backwards, going from 3.73's to 4.09's in my car with the GT350 wheels gave the same increase in road force as if the peak torque increased by about 40 ft-lbs.

Today I was on a 35 mph road in 3rd and floored it. It just leaped forward and I was hanging on for dear life. In the blink of an eye I was doing 82 and a garbage truck was coming around the bend...whew that was a butt pucker.
 

cib24

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Does anyone have one of the diagrams/calculus showing the gearing rpm to speed per gear charts...? (Looks like a saw blade)

I would need to see them side by side, before I could make a decision.
Gearing at 7400 RPM on 27.7" tyre with 2018 MT82-D4 gear ratios

upload_2019-7-4_10-15-56-png-png.png
 

Ontheedge

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All done. 10 minute run yesterday on jack stands went fine, although there was a loud clank the first time I put it into reverse, I basically dropped the clutch and there was no weight on the wheels. Let it sit overnight, then took it out today for a 15 mile test drive. Not a drop of fluid on the garage floor after sitting overnight. No hard acceleration yet, still breaking them in. NOTICEABLE improvement in acceleration, especially 2500-4000 rpm in 3rd gear. Ran it at speeds up to 75 mph, no vibration, whining, or roaring - smooth as butter. Very driveable and shiftable. If I'm careful with the clutch, there's no clank putting it into reverse, maybe it just sounds louder because the gears are a steeper angle or something.

At 2000 rpm in 3rd gear with the 3.73's I was going 31 mph, now with the 4.09's it reads 28 mph, which lines right up with the predicted calculated speeds. It adjusted to the new gears automatically like other people have posted.

So it's still early but as of now, to quote Gene Hackman in Hoosiers: I regret nothing.

Side note: If you lined up two of my car next to each other, one with the X-pipe and one with the H-pipe, I'd never be able to tell them apart.
Did you have to adjust the final gear in the computer from 3.73 to 4.09. I ask beacuse i was in contact with my ford dealer about changing the final gears, and he say to me that it will need a tune to change the ratio in the pcm, orels the readout will be wrong and then my warranty is by by.
 

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Mikepol2

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Did you have to adjust the final gear in the computer from 3.73 to 4.09. I ask beacuse i was in contact with my ford dealer about changing the final gears, and he say to me that it will need a tune to change the ratio in the pcm, orels the readout will be wrong and then my warranty is by by.
I did not have to adjust the computer. The speedometer corrected itself but I don’t know if only 2018+ does that or if all S550’s do that.
 

DekiDoo

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Did you have to adjust the final gear in the computer from 3.73 to 4.09. I ask beacuse i was in contact with my ford dealer about changing the final gears, and he say to me that it will need a tune to change the ratio in the pcm, orels the readout will be wrong and then my warranty is by by.
Your dealer is wrong, you won't need to tune your speedo for a gear change, only for tire size.
 

MRGTX

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Your dealer is wrong, you won't need to tune your speedo for a gear change, only for tire size.
Evidentially, there is a parameter in the as-built firmware that corresponds to the final drive ratio...so can anyone conceive of how the wrong ring and pinion setting could mess things up? What is the software using that parameter for?

My 4.09s and install kit are here...just debating about buying a FORscan link or whatever...though I really don’t feel like getting into that just yet.
 

barron64

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In terms of bang for the buck...Going from 3.73's to 4.09's for 6sp 18 models and up has to be towards the top of the list. The 10sp automatic models have 1-6th gear as underdriven, 7th is 1:1 and 8-10 gears are overdrives. The 18's and up only have 1-3rd as underdriven, 4th as 1:1 and 5 & 6th as overdrives. No wonder the automatics have an advantage...They have twice as many underdriven ratios below their 1:1 direct gear.

Has anyone got any comparison times/speed (1/4mi) from going from 3.73's with an 18 and up, 6sp, vs 4.09's?
 

MRGTX

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Evidentially, there is a parameter in the as-built firmware that corresponds to the final drive ratio...so can anyone conceive of how the wrong ring and pinion setting could mess things up? What is the software using that parameter for?

My 4.09s and install kit are here...just debating about buying a FORscan link or whatever...though I really don’t feel like getting into that just yet.
So it seems like nobody knows...the only unanimous commentary is that the speedometer is not affected by the ratio change.

I was just reading the description on LMR’s page and they mention that the speedo will need to be recalibrated but if that’s not true, can we deduce that no software update is actually necessary?
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