Rear Diff Cover

[Bahndvr]

Good point on the Torsen. None of EU cars have a Torsen from factory. But I am putting a Torsen in mine with a 4.09 final gear. The diff is already assembled and waiting to be put in. That will produce plenty of heat. So one piece for testing will also go in my car. But I will not have comparable before and after numbers because from factory the car has a 3.55 gear with clutch type LSD. The only thing I will be able to say is if it works enough to not go into reduced engine power mode.

4.09 Wow I guess you don't intend to do many Autobahn runs. I have 3.73 and my Torsen has barfed after a hard Autobahn run.
May I ask what your intended use will be?
Oh, you can put heat tape on the rear diff, go for a hard drive and then look at the tape to see how hot it got.

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[FluiX]

This is not a very high quality picture, but I guess it will do the job. As the bracket is only beyond the exhaust pipes I would guess, it should be fine.

That is no problem at all. It is relatively far aft of the entire differential.

 

[FluiX]

4.09 Wow I guess you don't intend to do many Autobahn runs. I have 3.73 and my Torsen has barfed after a hard Autobahn run.
May I ask what your intended use will be?
Oh, you can put heat tape on the rear diff, go for a hard drive and then look at the tape to see how hot it got.

Actually the 4.09 is nearly perfect. Maybe 3.91 would be better but only a few manufacturers make that. With the 4.09 you reach 295 km/h (184 mph) in 5th gear at factory redline. Without fooling some electronics, the maximum speed limit you can raise the GT to is 300 km/h anyways (187 mph), so that will be fine. With our EU 3.55 final gear I find the car does not accelerate well enough on the Autobahn. In 4th gear the car can go 276 km/h (172 mph) mechanically which is absurdly long and takes away too much torque at the wheel (15% compared to 4.09). If you have a supercharger in your car you might not care however .

But intended use is hard Autobahn with occasional track days.

Yes, I plan on doing the heat tape. But I also enabled the rear axle temperature gauge in the digital dash via Forscan. Our EU diffs do have a temperature sensor but the digital dash does not show the temperature from factory.

EDIT: I just saw you have a 2016 GT. You have a totally different MT82 compared to the facelifts. your 1:1 gear is 5th gear so you are fine with a 3.73. On the 2018+ 1:1 gear is in 4th. Gear 5 and 6 are overdrive at ratios 0.81 and 0.62 respectively. That's the reason why many people complain that the facelift, especially with the 3.55 final gear is sluggish. The EU models do not get the PP diffs with the 3.73 and Torsen at all, which is a shame. Surely to save some fuel and get better emissions certifications.

 

[Bahndvr]

Actually the 4.09 is nearly perfect. Maybe 3.91 would be better but only a few manufacturers make that. With the 4.09 you reach 295 km/h (184 mph) in 5th gear at factory redline. Without fooling some electronics, the maximum speed limit you can raise the GT to is 300 km/h anyways (187 mph), so that will be fine. With our EU 3.55 final gear I find the car does not accelerate well enough on the Autobahn. In 4th gear the car can go 276 km/h (172 mph) mechanically which is absurdly long and takes away too much torque at the wheel (15% compared to 4.09). If you have a supercharger in your car you might not care however .

But intended use is hard Autobahn with occasional track days.

Yes, I plan on doing the heat tape. But I also enabled the rear axle temperature gauge in the digital dash via Forscan. Our EU diffs do have a temperature sensor but the digital dash does not show the temperature from factory.

EDIT: I just saw you have a 2016 GT. You have a totally different MT82 compared to the facelifts. your 1:1 gear is 5th gear so you are fine with a 3.73. On the 2018+ 1:1 gear is in 4th. Gear 5 and 6 are overdrive at ratios 0.81 and 0.62 respectively. That's the reason why many people complain that the facelift, especially with the 3.55 final gear is sluggish. The EU models do not get the PP diffs with the 3.73 and Torsen at all, which is a shame. Surely to save some fuel and get better emissions certifications.

Just saw you have a 2019. Just realized since you mentioned my 2016.

I had heard years ago that the 3.90 was that perfect balance, especially for the automatics.

It will be good to hear from you after you have ran the diff cover for awhile.

 

[CVCashmere]

I am not quite sure which extra subframe portion you are speaking about. I don't know the extra reinforcements on the convertibles too well. Can you post a picture? Of course the part was designed more in mind for the PP and PP2 (Fastback) drivers who go to the track. But the external dimensions of the diff cover are identical to the OEM cover towards the rear and top of the car. It is only bigger due to the fins towards the bottom and the front of the car. Therefore, I think it will probably fit, but I could verify with a picture.

here are 2 more pictures of the Vert subframe in the rear.

These are from the 2019 LA Auto Show and not mine.

This should provide adequate detail as to the subgrame location.

thanks

CVCAshmere

 

[FluiX]

here are 2 more pictures of the Vert subframe in the rear.

These are from the 2019 LA Auto Show and not mine.

This should provide adequate detail as to the subgrame location.

thanks

CVCAshmere

That is definitely no problem and not in the way at all. So for the convertible it will also work.

 

[racingandfishing]

Good point on the Torsen. None of EU cars have a Torsen from factory. But I am putting a Torsen in mine with a 4.09 final gear. The diff is already assembled and waiting to be put in. That will produce plenty of heat. So one piece for testing will also go in my car. But I will not have comparable before and after numbers because from factory the car has a 3.55 gear with clutch type LSD. The only thing I will be able to say is if it works enough to not go into reduced engine power mode.

Any update?

 

[FluiX]

Any update?

I am waiting on the fitting for the vent line of the diff cover for 3 weeks. When I receive it I can install and gather data. This fitting should arrive this week and then I will move forward and keep you informed on this thread.

 

[WD Pro]

I’m very interested in this and fully understand the level of engineering and investment you’ve sunk into this project

I’m an EU car, but I have the FP Torsen and 4.09 gear set sat in the garage for a future install - it could make sense to do everything at once

WD

 

[FluiX]

I’m very interested in this and fully understand the level of engineering and investment you’ve sunk into this project

I’m an EU car, but I have the FP Torsen and 4.09 gear set sat in the garage for a future install - it could make sense to do everything at once

WD

Thank you . There should be good data to back up the design soon. And you definitely want to change everything at the same time unless you have very good patience to do it twice within a short time .

 

[JohnVallo]

When I was asked to test this newly-designed finned S550 Diff cover, I was a bit humbled, somewhat honored, but mostly excited. The designer/creator of the cover is from Munich Germany, -he goes by Ish, or his forum name: FluiX. FluiX is the abbreviation for his company: Fluid Dynamic Experimentation and Technology.

The only thing that was requested of me was to give an honest test and a non-biased evaluation of the new piece, and that is exactly what I intend to do here. I want to give a first-look evaluation of the piece now and later I plan on creating a new thread, maybe called: (Inside the "Super 8.8" rear end) with a deep-dive into the internals, detailing an overhaul of a S550 carrier with new bearings & seals and hoping to offer some good information. Then I plan on putting the Fluix cover onto this unit and swap it into my car for some diff temp testing.

I Received the FluiX cover on Oct 6, 2020
At first appearance the new finned cover looks to be, well designed, a high quality, and excellent machine work (looks just as good, if not better than the OEM factory machining)

16 External Fins running along the bottom, and across the back of the cover.
Most definitely these should dissipate heat.

Someone must have maybe been listening to Gale Banks as the 13 internal ribs obviously are there to direct the fluid, reduce foaming, and reduce heating effects.

Comparing the outside of a Stock OEM cover (Left), to the FluiX cover (Right)

Here is the inside comparison, I also did a weight comparison,
Factory OEM diff cover (wo/cooler), weight: 7lbs, 10.3oz
FluiX finned cover, weight: 13lbs, 1.7oz

Clearance wise, (at the back of the covers), They are both the same depth.

I did a fluid Volume capacity comparison on each cover.
I sealed a glass plate to each cover, stood it up vertically and filled with liquid to the fill hole.
Both the stock OEM cover and the FluiX cover held 16 oz.

Here's some additional close-ups of the cover at different angles.

 

[WD Pro]

It looks to be a very impressive piece of kit

WD

 

[JohnVallo]

While on the subject of OEM diff covers for the S550, I was asked to share some of my experience with the Stock OEM Covers

Basically 3 different OEM Part Numbered diff covers are used on the S550.
1. Factory OEM diff cover, PN: FR3Z-4033-B, 15-20 Shelby GT350 (w/cooler),
2. Factory OEM diff cover, PN: FR3Z-4033-C, 15-20 Mustang, EcoBoost, EcoBoost Premium, GT, GT Premium, V6
3. Factory OEM diff cover, PN: FR3Z-4033-D, 2015 Mustang & Shelby(wo/cooler)

Here are the 3 covers:
Left: (FR3Z-4033-D), Center: (FR3Z-4033-C), Right: (FR3Z-4033-B)
FR3Z-4033-D and FR3Z-4033-C are nearly identical, while FR3Z-4033-B has the extra hole for the cooler fitting, and the (2) PN: DR3Z-6K741-A cooler fittings installed.

There is another part number listed in the Ford inventory: PN: GR3Z-4033-A
I’m not sure what exactly this fits as it may be a part that supersedes another from above.
Here is the description in the parts inventory, If someone can figure this out, please let me know:
Description:
With gt350. Mustang. Carrier, without shelby.

Most all the OEM diff covers will accept a Ford Temp Sensor unit, although all covers do not have a sensor installed from the factory.
The M10 x 1.5 threaded hole for it is usually already there (in all the covers I've had).
Although here is one that looks like it doesn't have the hole for the Temp Sensor (WTF ?)

On 3/1/18, I ordered a new FR3Z-4033-D cover from Ford parts. It did not look like the one above. It did have the Temp Sensor Hole. My cover came with the internal vent steel cover plate and screw on the inside. (A T25 torx male bit socket is needed for the screw holding the cover plate to the inside of the cover.) It did not come with the press-in aluminum Vent fitting located on the outside.
I had to order this Vent fitting part separately, PN: 2L1Z-4022-BA

Ford OEM Temp Sensor unit: PN: 9L8Z-6G004-E

If you need a wiring pigtail to fit the sensor:
Wiring Pigtail for Sensor: Motorcraft PN: WPT-984

Not sure about the Mustang GT's, But on my 2016 GT350 I was able to enable the OEM factory dash display to show the axle temp, by adding the above parts, doing some wiring, and using Forscan software to make the dash display work.
See the following Link for detailed description::
https://www.mustang6g.com/forums/threads/gear-change-from-4-11-rear-gear-to-4-56-in-my-gt350.104766/

Cover Bolts
The bolts that hold the rear cover to the housing are: 10mm x 1.5 , Inverted Torx headed bolts.
You may need an E-Torx female bit socket, (E-18) for these inverted Torx cover bolts.
Myself, I have been getting-by, by using a worn 13mm metric socket.

Ford uses longer cover bolts on cars with the aluminum diff housings
The bolts that are used on the aluminum housing are approx. 10mm Longer than the bolts that are used for an iron housing.

8 of the 12 holes in the housings go all the way through, but the 4 threaded holes in the center, (on each side of the half shafts), do not go straight through, and you guessed-it, these threaded holes are drilled deeper with more threads on the aluminum housing, to accommodate the longer bolts.

The best silicone/gasket sealer to use
I have tried several, No-doubt the best silicone sealer I have found is the Motorcraft (TA-19),
It is the same sealer used by Ford for the Factory assembly.

Drain and Fill Plugs
If you are sourcing the drain/fill plugs, or just replacing them, be sure and use the Ford Plugs: PN: 5R3Z-7860108-AA, as they contain magnets imbedded into the plug itself.

Differential Mounting Bolts
Many users (Me included) have opted to upgrade the Diff Mounting Bolts for the S550.

Here are some links if this interests you.
BMR Differential Hardware Upgrade Kit
https://www.bmrsuspension.com/?page=products&productid=1764&desktop=1

Lethal Performance S550 IRS Extreme Differential Bolt Upgrade Kit
https://www.lethalperformance.com/lethal-performance-s550-extreme-diff-bolt-upgrade-kit.html


Here is a great discussion of the Diff Bolt Problem.
https://www.mustang6g.com/forums/th...al-mount-bolts-issues-resolutions-pics.74891/

**NOTE** Looking at the back of the cover, on the Right Side, just under the mounting bolt boss, is the build date stamp of the cover.

 

[Bahndvr]

This is great have all this info in one place

 

[racingandfishing]

I have a 2015 with a 2018 speed/tach cluster that has the rear axle temp gauge. Does anyone know if the pigtail can be wired into a 2015 without the sensor to make it work?

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