Rear differential

[Burkey]

Something seems funny. If the rear end needed to be stronger, for what ever reason, (iron) the A10 would need it more than the manual IMHO.

Erm....no. You might think your auto hits hard, but nothing hits the driveline harder than a manual that’s being properly abused.

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[HoosierDaddy]

Do you need the whole pumpkin? If not get a ring and pinion and research on how to change them, I know the youtube has it.

Just FWIW, for a DIYer that is a much harder thing to do right. Anyone who can turn a wrench can swap the pumpkin. Setting gears up right is not likely to end up quiet or reliable if you haven't done it a lot. If you're paying someone to do either, not a factor as long as you pick the right person to do the gears.

 

[BmacIL]

Do you have a Pic of the other sticker on the back of the cover?

It's almost certainly a 3.55 auto trak lock (clutch pack) diff though.

 

[TexasRebel]

Torsen roar?

...and I really hope nobody tried to stuff a GM posi into a Ford Super 8.8.

 

[Cobra Jet]

I saw this for sale. Guy said he doesn't have any info on it.
Says low mile posi 3:55.
Only the one pic.
Can anyone familiar with these get any info from this pic?
Auto?
Manual?
Aluminum?
Said he bought it on Ebay but original posting has even less info.
Sent me this number:
JR3Z-40000-F
Thx.

That is a pre-2018 case.

Meaning it is a cast aluminum case with cast aluminum rear cover. Most likely came from a 2015-2017 EB PP (auto or MT82).

I can’t tell from the pics if that is an MT82 rear pinion flange OR one from a 6R80.

———

Going from memory, I think the 2015-2017 GT PP MT82 pumpkins were supposedly iron w/optional Torsen, while the 2015-2017 GT w/ 6R80 was iron with standard trac-lock. The 2015-2017 iron case was bare, so if looking at it, the case will be “rust” color.

2015-2017 EB 6R80 or those with MT82 were strictly aluminum case w/ standard traction lock.

There were many options for the 2015-2017 rear pumpkin depending on the platform chosen. So I am not sure if I’m covering all available case/gear types....

The 2018-2019+ GT or EB PP’s all come with iron pumpkins and Torsen. The 2018-2019+ iron case will be coated black with a cast aluminum rear cover. Also to note, the 2018-2019+ GT/EB PP rear covers will have the included threaded port for the rear axle temp sensor.

A) The 2018-19+ GT w/ MT82 came w/ Torsen and 3.73’s.

B) The 2018/19 GT or EB w/10R80 came w/ Torsen and 3.55’s.

The main difference between ALL S550 pumpkins will be the rear pinion flanges between a MT82 and those of the 6R80/10R80 pumpkin. From what I can remember if buying a complete used or new pumpkin w/X-gears, you should not get a MT82 pumpkin for a 6R80/10R80 and vice versa... the rear pinion flange would have to be swapped to mate with X-trans.

Other notes for all S550’s:
1) The physical pumpkin and mounting points are the same between all S550’s, it’s just the rear pinion flange that will vary based on what trans it was associated with (or going to be mated to if swapping rears).

2) Due to the variance in the rear pinion flange, you must source the correct driveshaft because the front trans flange coming off the trans (MT82, 6R80 or 10R80) will have to match to the proper driveshaft.

3) I haven’t dealt with any 3.15’s, however from what I can recall (and based on many threads), if the car has a factory 3.15 pumpkin, the gear ratio can’t be easily changed (or requires more R&R hoops to jump through) due to the 3.15 pumpkin interior sizing. Don’t quote me on this, because I’m not 110% certain of the exact issue - but from what I’ve seen, most who have a 3.15 just get a complete pumpkin w/X-gearing for their application.

//////////////////////////////

If buying a used S550 pumpkin from unknown sellers (off this site) - be careful. Some of the early S550 pumpkins were warranted out due to premature internal gear wear. Probably more prevalent with the 2015-2016 “vibe” issue (huge thread in Issues/TSB forum for those who want more info).

Buy from reputable Sellers or support the Vendors on this site who sell brand new loaded pumpkins.

 

[Daryl333]

Do you have a Pic of the other sticker on the back of the cover?

It's almost certainly a 3.55 auto trak lock (clutch pack) diff though.

No that is it.

 

[Daryl333]

Torsen roar?

...and I really hope nobody tried to stuff a GM posi into a Ford Super 8.8.

Just stuff I researched on this site. Some have called the noise from the diff as their Torsen roar. That's what I punched into google which brought up this site.

 

[ctandc72]

Just to add

My former 2017 V6 Mustang / 6 speed - factory 3.15 geared was an IRON case diff. Every manual trans differential from 15-17 (EB, V6 or GT) I've seen has been iron case, alum cover.

Also it's much easier to swap pumpkins unless you have or know someone with the tools to correctly set up gears. Not to mention - if you are starting with 3.15 gears, you HAVE to change the differential to use steeper (higher numerically) gears. Just good gears and install kit is $300 - not to mention having to buy a differential if coming from 3.15 gears. Swapping the complete pumpkin is easy and takes only a couple hours if you've never done it before.

Most places that install gears also will not let you bring your own parts - they won't warranty customer parts - so you're looking at $500-800 for a gear swap easy - again - unless you know someone or have a hook up.

 

[Ebm]

Just FWIW, for a DIYer that is a much harder thing to do right. Anyone who can turn a wrench can swap the pumpkin. Setting gears up right is not likely to end up quiet or reliable if you haven't done it a lot. If you're paying someone to do either, not a factor as long as you pick the right person to do the gears.

Bingo. Leave this job to a professional who does gear swaps often. If you don't get all the adjustments right, you'll have a howling rear-end or worse.

 

[VooDooDaddy]

...Just want a more spirited throttle response.

You might want to consider an aftermarket torque converter such as a Circle D 3C?

 

[ctandc72]

https://www.ebay.com/itm/15-19-Ford...0aeca84654a78eb1551ce63e2f&LH_ItemCondition=4

One example. I'm assuming you have 3.15 gears? Swapping to 3.55 gear from 3.15 in my '17 V6 was worth every penny and the few hours it took to install.

I've got a brand new set of Ford Performance 3.73 gears and install kit (that I was planning on installing in my '17) that might find it's way into my '19 GT 6 speed.

 

[HoosierDaddy]

You might want to consider an aftermarket torque converter such as a Circle D 3C?

The OP has a manual trans otherwise a good idea.

OOPS

 

[TexasRebel]

Just stuff I researched on this site. Some have called the noise from the diff as their Torsen roar. That's what I punched into google which brought up this site.

Ah, just wondering, because the whole point of a Torsen style differential is to smoothly apply power to the high traction wheel in partial slip conditions. In fact, there aren't any spur gears (noisy gears) in the T2R.

 

[Jetnoise]

Something seems funny. If the rear end needed to be stronger, for what ever reason, (iron) the A10 would need it more than the manual IMHO.

I completely disagree with that one.

The 3L55 is a posi, but Torsen are labeled with an L too

My 18 PP 6 speed has a steel carrier. Not alloy.

The pictured aluminum case one in the OP sure looks good and I'd choose swapping a pumpkin over a r&p swap any day of the week! What's the price ??

 

[VooDooDaddy]

The OP has a manual trans otherwise a good idea.

Ooops! That one slipped right by me...

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