31 spline axles what fits?

ripped camel

ripped camel

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I'm just curious if I were to buy an 03/04 Cobra limited slip differential, would I also be using the 31 spline axles from an IRS stang? I wasn't sure if the length was different for our cars.

I'm not buying this now, I'm just gathering intelligence for my next project I plan on tackling.

I'm thinking of going 03/04 Cobra diff with carbon fiber disks, 4.10 gears, 31 spline axles and switching the rotors brakes over obviously to match the axles to accept Mustang wheels.

I wanted to do it all in one fall swoop. I just wanted to make sure the axle would fit before I set my sights on this setup.

Btw, wtf is with people wanting so much for a used diff? I see people asking as much as $150 - $200! I'm floored they want that much when you can buy a new 03/04 cobra unit for $219 and regular 28 spline limited slip setups for $194! Blows my mind! Everyone thinks their parts = gold and for because so many people are clueless they actually pay it!
 
Are you talking about people selling a whole carrier and housing? Or just a differential carrier? That may contribute to the price difference.
 
DieselDan said:
Are you talking about people selling a whole carrier and housing? Or just a differential carrier? That may contribute to the price difference.
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I was complaining about people selling just the differential. I see them asking the prices I said for JUST the differential.

That was just my little rant as I was searching for a cheap 28 spline setup so I can do a swap now. As I saw how ridiculously these things were priced used I decided to wait and go the other route.
 
slowmkviii said:
I have 03/04 cobra different and axles in my car
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Cool so standard 31 spline 03/04 axles will work with our car? But we need to switch to Mustang rotors, brakes and wheels then right? What did you do?

Did you notice a huge difference in traction with the 03/04 unit paired with 31 spline axles as opposed to the factory mark setup?
 
I'm assuming you know this... but you would be going from an open diff to a limited slip, so that alone would be a huge increase in traction.
 
DieselDan said:
I'm assuming you know this... but you would be going from an open diff to a limited slip, so that alone would be a huge increase in traction.
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Yeah I know that. I was in Jamies car and it was a huge increase from what my car is to that. I was just curious if it was intensified even further going to the 31 spline carbon disk setup.
 
Well, you arent going to feel any difference with the number of splines, the 31 spine applications were usually used in higher HP vehicles or where they needed more strength(like an explorer) So you are putting in a stronger component if you get 31s, but you arent going to feel any kind of difference.
 
you dont have to do anything to the outter... they are all the same 31 and 28 only matter at the center section on these and the cobras... same amount of splines on the outside.

So you could use all your stock wheels brakes etc
 
Staffamerica74 said:
you dont have to do anything to the outter... they are all the same 31 and 28 only matter at the center section on these and the cobras... same amount of splines on the outside.

So you could use all your stock wheels brakes etc
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Wait, now I'm confused.

1. I thought if I went with the 31 spline Cobra axles, that the bolt pattern on the axle would require the use of cobra rotors, axles and wheels.

2. What is the center section? Are you referring to the housing that hold the differential or the differential itself?

3. So to sum it up I can install the 03/04 Cobra diff, 31 spline axles and 4.10 gears in my existing housing and setup and need nothing else?
 
ripped camel said:
Wait, now I'm confused.

ripped camel said:
1. I thought if I went with the 31 spline Cobra axles, that the bolt pattern on the axle would require the use of cobra rotors, axles and wheels.
Click to expand...
No the outer axle has the same spline count as the Marks.

ripped camel said:
2. What is the center section? Are you referring to the housing that hold the differential or the differential itself?
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The housing side which included the side gears in the dif which is what you are talking about when saying 28 or 31 spline.
ripped camel said:
3. So to sum it up I can install the 03/04 Cobra diff, 31 spline axles and 4.10 gears in my existing housing and setup and need nothing else?
Click to expand...
Sounds like it based on what was said but I have not done this
Click to expand...
 
1) This is the outer stub shaft, not the wheel hub. The inner stub shaft has 28spines on Marks/ Thunderbirds and 99 Cobras. 01 Cobras and up, have 31 spines.

2) The center section refers to the whole unit. Better known as "the pumpkin" The differential is inside. Better known as a "t-lok or traction lok".

3) Correct. IF you decide you want mustang wheels, or any 5X4.5" bolt circle wheel, then you will have to change the wheel hub.

Now, as far as replacing the differential, find one from a 99 cobra and your done. YOu don't need 31 spline units. 28 splines will do just fine. Also, 03/04 cobra shafts are 31 spline at the pumpkin, and 28spline at the wheel hub. Unless your making 600 hp, they really are unecessary.
 
Along with the carbon fiber clutches... overkill for most marks. They are nice however because they hold a lot more torque. Pack a few more of those in there and it will pretty much never spin one wheel... heck put a detroit locker in it...LOL

Anyway, If you are on a mustang forum (like me) those kind of parts are generally cheap. especially a 28 spline diff.. could almost get them for $50 all day long. heck I've got 2 or 3 myself. Switched to 31 spline explorer carrier and put carbon fiber clutches in it. But I'll be launching my '88 at 5500 on the 2-step with slicks.
 
Stangman said:
Along with the carbon fiber clutches... overkill for most marks. They are nice however because they hold a lot more torque. Pack a few more of those in there and it will pretty much never spin one wheel... heck put a detroit locker in it...LOL

Anyway, If you are on a mustang forum (like me) those kind of parts are generally cheap. especially a 28 spline diff.. could almost get them for $50 all day long. heck I've got 2 or 3 myself. Switched to 31 spline explorer carrier and put carbon fiber clutches in it. But I'll be launching my '88 at 5500 on the 2-step with slicks.
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I was on corral, svtp, mustang forums looking and they were all really expensive. It's like they thought they had gold. I was floored because as I said a brand new 03/04 Cobra one is only $219.99. I was hoping to score a basic 28 spline limited slip for like $50 so I could do gears sooner, rather than later, but I refuse to pay $100+ for a used setup.
 
If your talking about what is on the work bench on the left hand side (diff, center section), that IS gold, I will charge you a $250 core charge for that till I get a customers take out unit back.

P101000510.jpg
 
The diff I got is out of an explorer with 31 spline side gears, but I have a set of 28 spine side gears to put in it to make it work in my car.
 
DieselDan said:
The diff I got is out of an explorer with 31 spline side gears, but I have a set of 28 spine side gears to put in it to make it work in my car.
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Dan, that's the carrier, lets not confuse the boy now ;)






Dr. SVO phd
 
I've always heard people refer to it as the pumpkin, or differential housing. I just never heard it called the center section, I assumed it was referring to the housing but wasn't sure. I'd rather play stupid and be schooled, rather than blindly walk around with false knowledge.

regarding price I was referring to just the differential, those seem to go for ridiculous prices.

So the mark viii housing/ center section is 31 spline on the housing side and 28 spline on the wheel side? In other words if I bought the 03/04 Cobra diff I would be able to use my stock mark axles on it?
 
I'm pretty sure that only 03/04 cobras and explorers used 31 spline side gears in the carrier. As far as stuff newer than 05, I dont know if any of this applies. Anyway, everything that uses an 8.8 has 28 splines at the wheel end. If you want a plug and play diff that will cost you the least, you need something out of a mustang GT, and I think some v6 cars had an 8.8 limited slip? They will have 28 spline side gears. The side gear is what you are sliding the axle shaft into at the differential. An 03/04 Cobra diff and explorers have 31 spined side gears, and are not "plug and play" with your current stock Halfshafts(axles) If you got either a carrier from an explorer or 03/04 cobra you will either need cobra axles, or I believe you can change the yoke on your shafts with 31 spline yokes, or do what I am doing and get an explorer differential, and install 28 spline side gears. Trying to be as lamen as possible but I dont know if it worked.
 
DieselDan said:
I'm pretty sure that only 03/04 cobras and explorers used 31 spline side gears in the carrier. As far as stuff newer than 05, I dont know if any of this applies. Anyway, everything that uses an 8.8 has 28 splines at the wheel end. If you want a plug and play diff that will cost you the least, you need something out of a mustang GT, and I think some v6 cars had an 8.8 limited slip? They will have 28 spline side gears. The side gear is what you are sliding the axle shaft into at the differential. An 03/04 Cobra diff and explorers have 31 spined side gears, and are not "plug and play" with your current stock Halfshafts(axles) If you got either a carrier from an explorer or 03/04 cobra you will either need cobra axles, or I believe you can change the yoke on your shafts with 31 spline yokes, or do what I am doing and get an explorer differential, and install 28 spline side gears. Trying to be as lamen as possible but I dont know if it worked.
Click to expand...

HAHA! Yeah I was having a hard time grasping that but I got it now.

Now about the 28 spline diff I thought because of abs or something we can only use the cobra model diff, and that the gt model wouldn't work with our cars. even supercoupe performance's website says the gt diff won't work, so does it or does it not?

http://supercoupeperformance.com/partBrowser.aspx?partId=599
 
Well... if you use a 8.8 trac lok out of somethign that is a solid axle, you need to remove your circlips off of your axles.
 
I think our ABS is picked up off of the halfshaft right at the differential housing. Some 8.8 carriers have an ABS ring on them. You don't need it on a m8.
 
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