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Torsen Differential Install

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TymeSlayer

Tramps like us, Baby we were born to run...
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Got my hands on New M-4204-MB Torsen Differential and was wondering if you guys have any suggestions for replacing anything else, for maintenance or otherwise, while I'm under there? I do have an Allstar differential breather I plan on installing as well.

Yeah, I didn't get that option on my Boss when I bought it new.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Bearings and shim kit to setup new differential.

You should have every covered with your new BMR suspension setup.

Why are you replacing? Looking to take some slop out with the new install and setup?

2HP
 

Grant 302

basic and well known psychic
I'd also consider replacing the axle bearings and seals. Inspect the axles for wear. And remember you don't need the friction modifier anymore.

I think you'll love the improved traction from the Torsen!
 
898
544
Like everyone else said, all new bearings and seals throughout the rear ended. You can get most of the parts in a Ford Performance installation kit. I believe the kit comes with axle seals, but they are not as good as the OEM motorcraft seals.

I can post up the part numbers later this weekend.
 
680
215
2012-Boss said:
Like everyone else said, all new bearings and seals throughout the rear ended. You can get most of the parts in a Ford Performance installation kit. I believe the kit comes with axle seals, but they are not as good as the OEM motorcraft seals.

I can post up the part numbers later this weekend.
The axle seals that come in the Ford Performance kits are OEM Motorcraft seals...
 
898
544
BigTaco said:
The axle seals that come in the Ford Performance kits are OEM Motorcraft seals...

They weren't in the last kit I bought earlier this year. They were timken seals and they didn't have the outer flange with sealant like the OEM seals. It may be because the only kit now listed with axle seals included is the M-4210-C3 which has seals for 8.8 rears made from 1986 through 2004. I mentioned it because I was surprised that they were not Motorcraft and there is a definite difference compared to OEM.

The correct installation and pinion seal kit for our cars is M-4210-B2, but it does not, or at least no longer comes with axle seals and bearings.
 

TymeSlayer

Tramps like us, Baby we were born to run...
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Thanks folks.

I already have the bearing kit M-1225-B1, a spare lube locker gasket and 3 qts. of Royal Purple 75W140. Would the M-4210-B2 kit give me everything else I'll need?
 
898
544
That's all you should need. You may need to use RTV on the differential cover instead of the lube locker gasket. The cover has a groove machined around the perimeter for a bead of RTV which may cause an issue with the gasket sealing properly.
 

TymeSlayer

Tramps like us, Baby we were born to run...
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2012-Boss said:
That's all you should need. You may need to use RTV on the differential cover instead of the lube locker gasket. The cover has a groove machined around the perimeter for a bead of RTV which may cause an issue with the gasket sealing properly.

Thanks bud.
I do have the FRPP 8.8" Aluminum Axle Cover with Differential Cooler Ports installed already and used the same lube locker gasket which worked just fine.
 

Grant 302

basic and well known psychic
TymeSlayer said:
Thanks bud.
I do have the FRPP 8.8" Aluminum Axle Cover with Differential Cooler Ports installed already and used the same lube locker gasket which worked just fine.

+1. Mine works just fine with the same cover. I'm not missing the RTV and cleanup there. When I did my first change on the GT, the factory RTV was still wet!
 
898
544
TymeSlayer said:
Thanks bud.
I do have the FRPP 8.8" Aluminum Axle Cover with Differential Cooler Ports installed already and used the same lube locker gasket which worked just fine.

That is good information to know. I will make sure to order one the next time I have the cover off rather than messing with the RTV.
 

TymeSlayer

Tramps like us, Baby we were born to run...
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Can anybody confirm which is the OEM Torsen that came with the 2012 Boss?

Ordered M-4204-MB which should look like this?

M-4204-MB%20I_zpsuplkl7iy.jpg
M-4204-MB%20II_zpsxnamy5vg.jpg

But what I got looks like this:

Sweet%20Lorraine%201628_zpsi5pavpbm.jpg
Sweet%20Lorraine%201629_zpsc04pwamv.jpg

The part I got it Marked CR3W-4026-AB - Also, on the box it shows Torsen part number 409000-2170 which a google search came up empty.
I'm a bit confused and am not sure Ford sent me the correct part. Do you think one is a T-2 and the one I got is the T-2R and if so, what's the difference?
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
The difference between the T2 and T2R is the torque split multiplier from different spool gear ratios. The T2R has a higher multiplier ratio, and is a bit more expensive. (Example: $850 to $1,250, but it's been a few years since I looked at going with the T2R)

One last thought, If you are running a Watts Link that bolts to the rear differential cover, I would omit any use of a rear cover gasket and run with the sealant to remove any gasket compression issues under max Watts Link loads on the rear cover. Just a thought.

Good luck with your install and keep us posted on your Torsen install.
2HP
 

TymeSlayer

Tramps like us, Baby we were born to run...
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I getting the feeling I did get the correct one but it's funny when I Google the M-4204-MB and look at images, they all look like the one I didn't get. I suppose it could be a file photo or an erroneous picture Ford released to their sellers.

Thanks guys.
 
You got the correct part. I just checked your part number from the one I had sitting on the shelf from my 2013 Boss and the part numbers are identical. Good luck with the installation and enjoy!
 

Grant 302

basic and well known psychic
There are 3 different units that I know of.
T-2 bias ratio of 2:1
Boss specific (I've seen it called both T-2 and T-2R) bias ratio of 2.7:1 This is the OEM/factory unit.
T-2R bias ratio of 4:1

The Boss unit was always the most expensive ~$1k or so. The other ones were cheaper.
 

Grant 302

basic and well known psychic
I don't really know about the part numbers, but I think the suffix -MB sounds right for the Boss specific unit.

And pretty sure it was the 4:1 T-2R in the FR500S cars.
 

TymeSlayer

Tramps like us, Baby we were born to run...
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Brighton, Colorado
Grant 302 said:
There are 3 different units that I know of.
T-2 bias ratio of 2:1
Boss specific (I've seen it called both T-2 and T-2R) bias ratio of 2.7:1 This is the OEM/factory unit.
T-2R bias ratio of 4:1

The Boss unit was always the most expensive ~$1k or so. The other ones were cheaper.

Grant, I've been watching this item for the past year and a half and had originally seen pricing over 1K. Now I started seeing them running for $850-$950. Then I ran across it from Buy Ford Racing from DPM for $799 shipped and pulled the trigger. I suppose getting it at such a decent price only added to my concern that I got the right part since it didn't look like the one pictured. Thanks to those who helped me get confirmation that I did indeed get the right OEM Boss Torsen for my 2012.

http://www.buyfordracingfromdpm.com/products/2012-MUSTANG-BOSS-302-TORSEN-DIFFERENTIAL.html
 

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