Rear differential

[Daryl333]

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.

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[VooDooDaddy]

It's an all aluminum housing/case.

It has 3.55 gears as designated by the two stickers, one on the bottom of the case that says in part, "3H55" and the other on the rear of the case that says, "3L55".

I don't know if it is from a manual transmission car or an automatic.

There is no way to tell how many miles are on it. Differentials are pretty damned robust, so even if it had 50K miles on it, as long as it wasn't ran dry of gear oil, it shouldn't be a problem. Basically believing the miles statement by the current owner is a leap of faith on your part.

 

[Linkster1666]

I don't think the car or the pumpkin cares if it gets turned by a manual or automatic.

 

[offroadkarter]

Aluminum case diffs were in automatic cars, manual trans cars got iron case diffs. This came out of an auto car.

 

[Linkster1666]

Just looking at the parts catalog, all GTs '15-'19 are the same part number, the Shelby's have a different part number.

 

[Linkster1666]

JR3Z-4310-A is the rear end housing for the Shelby GT350

JR3Z-4310-B is the housing for the GT.

 

[Daryl333]

I don't think the car or the pumpkin cares if it gets turned by a manual or automatic.

I think I might have to pass

 

[offroadkarter]

Just looking at the parts catalog, all GTs '15-'19 are the same part number, the Shelby's have a different part number.

I have a funny feeling because all 2018+ cars are iron case, they might have superseded the part number into a one size fits all ordeal. I'm sure someone at a dealer could find the PN for the aluminum case

https://www.mustang6g.com/forums/threads/rear-end-swap-question.124483/#post-2585465

 

[Linkster1666]

I think I might have to pass

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.

 

[Linkster1666]

I have a funny feeling because all 2018+ cars are iron case, they might have superseded the part number into a one size fits all ordeal. I'm sure someone at a dealer could find the PN for the aluminum case

https://www.mustang6g.com/forums/threads/rear-end-swap-question.124483/#post-2585465

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.

 

[offroadkarter]

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.

The original point behind the iron diff housing was for the MT82 cars. I believe back in the early days of this platform some guys put aluminum housing rear diffs in stick cars and broke the housings apart with launching on slicks or something like that. I'm sure Ford either theorized or experienced this problem in testing which is why they already that situation rectified.

The automatic isn't going to shock the driveline like a clutch drop will. I'm sure after 2018+ they just put iron in all cars for simplicity and money sake.

 

[Daryl333]

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.

No I don't need the whole assembly. Just want a more spirited throttle response. Would doing just gears be more quiet than the Torsen roar?

 

[Linkster1666]

The original point behind the iron diff housing was for the MT82 cars. I believe back in the early days of this platform some guys put aluminum housing rear diffs in stick cars and broke the housings apart with launching on slicks or something like that. I'm sure Ford either theorized or experienced this problem in testing which is why they already that situation rectified.

The automatic isn't going to shock the driveline like a clutch drop will. I'm sure after 2018+ they just put iron in all cars for simplicity and money sake.

I'd like to introduce you to the Line-Lock feature. lol

I don't know but this auto hits hard when it shifts in drag mode.

The rear-end in my car is Al-u-min-ium, so I'm good and ignorant, no clue.

 

[Linkster1666]

No I don't need the whole assembly. Just want a more spirited throttle response. Would doing just gears be more quiet than the Torsen roar?

Nope, you will still have that, all you are changing is the ring gear, and the pinion and stuff.

 

[offroadkarter]

I'd like to introduce you to the Line-Lock feature. lol

I don't know but this auto hits hard when it shifts in drag mode.

The rear-end in my car is Al-u-min-ium, so I'm good and ignorant, no clue.

I've got line lock in my car as well, don't worry.

Since @Cobra Jet seems like an authority on differentials in these cars, maybe he can pop his head in.

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