How are people liking 4.09 gears in the MT82?

[Sik19GT]

This is super encouraging and I am tempted to try this myself.Iwill have to admit some fear in disassembling my brand new daily driver car that I rely on.

It really wasn't that bad to do myself. I used to be a tech about 5 years ago. The hardest part was honestly maneuvering the diff by myself. That thing was heavy!

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[Mikepol2]

See my post 34 above and this post for tips on doing the diff removal / reinstall yourself:

https://www.mustang6g.com/forums/th...erential-housing-install.103235/#post-2589358

 

[WD Pro]

My new toys have arrived :

Looks like they’ve got approval from Jess and Jasmine ...

WD

 

[MRGTX]

My new toys have arrived :

Looks like they’ve got approval from Jess and Jasmine ...

WD

I love that picture! Cats love hot rod parts I guess!

Please keep us posted.

 

[WD Pro]

Jess is my in house QC inspector ...

WD

 

[Mikepol2]

I still don’t have a good sense as to when the torsen proves itself to be that much better. I gather that cars that get tracked wear out the clutches in the track lock style rear relatively quickly...but does the torsen perform that much better?

Was reading an article in Motor Trend on their first test of the GT500 (which comes with the 3.73's and Torsen just like our normal-guy cars) and thought you might be interested in this quote:

"This massive thrust twists a trick carbon-fiber driveshaft into a Torsen gear-type limited slip—a good choice for a front-engined chassis, because it doesn't lock up much off power. This helps get the GT500 pointed into the turn, and it's also a non-wear item, unlike the clutch-type diffs."

This is kind of what I was trying to describe when I said it almost feels like 4 wheel steering and the back end rotating around for you.

 

[MRGTX]

Jess is my in house QC inspector ...

WD

Now you just need to teach him how to set the gear lash!

Was reading an article in Motor Trend on their first test of the GT500 (which comes with the 3.73's and Torsen just like our normal-guy cars) and thought you might be interested in this quote:

"This massive thrust twists a trick carbon-fiber driveshaft into a Torsen gear-type limited slip—a good choice for a front-engined chassis, because it doesn't lock up much off power. This helps get the GT500 pointed into the turn, and it's also a non-wear item, unlike the clutch-type diffs."

Thanks!

I’m pretty sure the TrackLoc doesn’t lock up off-power either though...The clutches engage when there’s uneven wheel rotation.IIRC, the amount of lock up can be tuned for acceleration and deceleration and I’m confident that Ford set those up to be as friendly as possible with minimal lift-oversteer.... if that’s true, It’s the wear and tear that seems to be the key difference.

I have visions of putting well over. 100k miles on this Mustang before even considering a trading it in, including autocross and possibly HPDE days...so it sounds like the Torsen will pay for itself.

 

[WD Pro]

OK, don’t shoot the messenger ...

Me to ford performance :

“Hi,

I am looking at installing the 4.09 gear (M-4209-88409A) in my UK spec 2020 GT with manual transmission, the car currently has a 3.55 gear.

After installation of the 4.09, do I need to alter any of the computer settings to ensure everything works perfectly ?

If so, what needs altering and what is the best way to do it ?

Thanks and best regards”

FP to me :

“You will have to find an aftermarket source that has a calibration for the gear change.

If you install gear without a calibration it will go into a protective mode”

Me to FP :

“Thank you for the confirmation.

Can the gear change calibration be amended through FORscan ?

Thanks and best regards”

FP to me :

“In the states the dealer system is IDS.

They cannot change calibration for any gear”

Make of that what you will ...

Does anyone have any more questions I should ask them ?

WD

 

[MRGTX]

OK, don’t shoot the messenger ...

Me to ford performance :

“Hi,

I am looking at installing the 4.09 gear (M-4209-88409A) in my UK spec 2020 GT with manual transmission, the car currently has a 3.55 gear.

After installation of the 4.09, do I need to alter any of the computer settings to ensure everything works perfectly ?

If so, what needs altering and what is the best way to do it ?

Thanks and best regards”

FP to me :

“You will have to find an aftermarket source that has a calibration for the gear change.

If you install gear without a calibration it will go into a protective mode”

Me to FP :

“Thank you for the confirmation.

Can the gear change calibration be amended through FORscan ?

Thanks and best regards”

FP to me :

“In the states the dealer system is IDS.

They cannot change calibration for any gear”

Make of that what you will ...

Does anyone have any more questions I should ask them ?

WD

ummm...I would save that communication somewhere safe. They just told you to use an aftermarket calibration in order to use a Ford part. Sounds like a free pass for not worrying about your warranty.

I don’t have any other advice here...interested in what others are thinking.

 

[Mikepol2]

I’m thinking my 4.09’s have been fun as hell for over a year with no PCM updates! The car certainly isn’t in any kind of “protective mode”, whatever that is, and drive modes work fine. I’d get back in touch with FP and ask to speak to a supervisor.

 

[wtb6mtv8rwd]

Great thread!

It's crazy that even equipped with 4.09 the 18-20 cars gears are still slightly taller than a 15-17 with 3.73.

Looks to me that 4.09 is a must-do mod on 18-20 for a fun street car.

FWIW here's a chart comparing 15-17 cars with 18-20 cars with 3.73, 4.09 and 4.56.
Showing top speed in each gear at max rev. Included 15-17 at 7500rpm also for comparison's sake even though they don't rev that high. Tire sized used is a PP2's 305/30/19.

 

[01Romanss]

Just got my 4.09 gears in today. In a word - phenomenal! I had my e85 tune on the car when I drove it home. I had lots of alerts about blind spot and pedestrian cross traffic not working. Also couldn’t access my drive modes. Make sure to load stock tune and do a KAM reset. That fixed it. Then loaded my e85 tune back on and went for a ride. Low gears are snappy and low end grunt is awesome. I absolutely love it on e85 and 4.09 gears.

 

[MRGTX]

I have an appointment to have my gears and torsen installed on Wednesday. I’m psyched! In all honesty, as much as I enjoy the S550, I still haven’t bonded with the 2020 like I did with my 2011. I’m really hoping this helps.


I am supplying the Ford Performance ring and pinion set, recommended install kit, OEM torsen diff.

Against all common wisdom, I’m having the stealership do the install. I’m reluctant to experiment with setting up gear mesh on my daily driver and the local shop that could do the job will only accept the work if I pull the assembly and bring it in myself. The dealership is quoting similar hours and will give me a loaner car...and preserve my warranty too.

Are there any special instructions that I should pass along before handing over the keys? Is the OEM gear oil adequate or would an alternate product be better?

Thanks!

 

[Mikepol2]

Nothing wrong with playing it safe with having the dealership install them, it’s not your average knuckle-dragging project. Not sure if there’s an advantage to specifying what oil to use or any other directions on how to do their job though. You can always change the oil later if you want.

 

[MRGTX]

Nothing wrong with playing it safe with having the dealership install them, it’s not your average knuckle-dragging project. Not sure if there’s an advantage to specifying what oil to use or any other directions on how to do their job though. You can always change the oil later if you want.

Thanks for not busting my chops over having the job done rather than doing it myself. I’m a pretty average (maybe slightly below average) mechanic but I’ve replaced/repaired/refreshed/tuned just about every nut and bolt on my Dodge...it just takes me 7x as long as it should! Can’t afford that risk with the daily.

There’s a bit of art involved in getting gear mesh just right. I’ve seen it done and it requires a level of precision and patience that I don’t always have on tap.

Good point about changing the diff oil later. I’ve done that job recently with my project and the pump is ready to go. That’s one I can handle.

Thanks!

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