Thinking about upgrading to 31 spline axles... [Archive]

MustangCRZY302

11-10-2008, 12:56 PM

After my pegleggin at the track a few weeks ago, i figured I'd just rebuild my stock diff, with new clutches etc. Then i got to thinkin, if I'm in there, I might as well upgrade the axles... So..

What do I need to do so? I've heard I could use a 03-04 Cobra's Diff, because they came with 31 spline axles.. any truth to this?

Also, if ya think its not worth the effort in finding a diff, ya thing I will be ok with just rebuilding the stock diff?

fast5.0

11-10-2008, 01:52 PM

i have just hardend 28 spline axles in my car if u go with 31 axles u will have to get a diff locker for 31s so i would just say rebuild your diff and get hardend 28 spline axles

BDASPNY

11-10-2008, 02:24 PM

i'm neck deep in a 5 lug conversion currently. i went with 31 spline axles and a 03/04 cobra diff. i'll let you know if it ever gets finished how much better i like it.

crumbie

11-10-2008, 02:54 PM

i have a rebuilt stock diff/traclok/posi with moser 28 spline axles. seems good enough for me so far.

MustangCRZY302

11-10-2008, 03:18 PM

i'm neck deep in a 5 lug conversion currently. i went with 31 spline axles and a 03/04 cobra diff. i'll let you know if it ever gets finished how much better i like it.

Sweet, thanx

31 Spline Mosers are $135/piece for 4 lug. And I'd REALLY like to stay 4 lug, for now, because I don't want to get 2 new sets of wheels. I'm leaning towards rebuilding the stock unit....unless I can get a Cobra Diff fairly cheap. How much ya think the stock axles can take? I'm putting down 401 TQ right now and that'll be going up when i swap out my injectors..

crumbie

11-10-2008, 04:19 PM

stock axles are hit or miss. my car makes no power and dead hooked some dr's and snap-oh.

SVTSkip

11-10-2008, 04:24 PM

Nova

11-10-2008, 07:12 PM

thought you could use a truck posi and mustang parts?

Silver91Hatch

11-10-2008, 07:23 PM

I have a 31 spline posi for sale from a Explorer in the Parts for sale section but I am working on shipping quotes for 4-5 people. The Explorer has a 7/8" pin and 31 splines, I think the Cobra is the same.

MustangCRZY302

11-10-2008, 09:28 PM

I'm doing the upgrade and staying 4 lug Adam. The reasoning is with a 28 spline at some point at the track you're going to break one. It might take longer ( I've seen folks go AWHILE ) than some, but it WILL happen. I wont even take my car to the track until I've done the upgrade...

Yea thats what i was thinking...

So besides the axles themselves, what else would I need for the swap?

rsw007

11-10-2008, 09:54 PM

find a used truck 31 spline carrier with 7/8 pin it will have bearings on it already. then all you need is axles and fluid. i add a extra clutch to mine. to make it stronger. im cutting cosistant low 1.4 60fts on drag radials.

SVTSkip

11-10-2008, 11:36 PM

Just the diff, and anything else you want to upgrade while you're at it like welding axle tubes, a Swarr bar, a diff cover, or whatnot. I also like to do seals and bearings anytime I'm in there...

Notch93

11-11-2008, 12:10 AM

I'm doing the upgrade and staying 4 lug Adam. The reasoning is with a 28 spline at some point at the track you're going to break one. It might take longer ( I've seen folks go AWHILE ) than some, but it WILL happen. I wont even take my car to the track until I've done the upgrade...

I'm upgrading also, and not taking the chance, if done right you should eliminate the c-clips also. But I have seen 28 spline hardened axles go well into the 9's.:yes1:

SVTSkip

11-11-2008, 12:34 AM

I've seen folks run fast with a 7.5 rear end too, but thats another one I wouldn't do myself either...

crossbreed

11-11-2008, 06:18 AM

go find a junk yard and a ford ranger take the carrier out and 2 left side axles and you will have 31 spline axles and carrier you want put a rear cover on it and your done.
or you can go all out like I just did on my wifes car 33 spline axles full spool c-clip elem. cover and 1/2" studs. and a anti-roll bar it went from a 2.20 60' to a 1.20 60' just my 2 cents

MustangCRZY302

11-11-2008, 08:59 PM

Just the diff, and anything else you want to upgrade while you're at it like welding axle tubes, a Swarr bar, a diff cover, or whatnot. I also like to do seals and bearings anytime I'm in there...

Yea i'd want to beef up everything I could. Swarr bar?

go find a junk yard and a ford ranger take the carrier out and 2 left side axles and you will have 31 spline axles and carrier you want put a rear cover on it and your done.
or you can go all out like I just did on my wifes car 33 spline axles full spool c-clip elem. cover and 1/2" studs. and a anti-roll bar it went from a 2.20 60' to a 1.20 60' just my 2 cents

Yea i thought that too, but i'm staying 4 lug for now.

Notch93

11-11-2008, 09:06 PM

33 spline axles full spool c-clip elem. cover and 1/2" studs. and a anti-roll bar it went from a 2.20 60' to a 1.20 60'

Yea i thought that too, but i'm staying 4 lug for now.

You can do what crossbreed said and stay 4 lug.:yes1: All depends on how much $$$ you want to spend. And how strong you want your rear built.

And most guys who drag race, will tell you to take the sway bar off and throw it in the trash. If you want to keep it on the car, just keep the stock one, unless your going road racing.

SVTSkip

11-11-2008, 11:36 PM

Swarr bar?

Yes. That would be one of these fine animals...

http://www.americanmuscle.com/swarr-bar-88-rear-86-04.html

MustangCRZY302

11-12-2008, 09:18 AM

You can do what crossbreed said and stay 4 lug.:yes1: All depends on how much $$$ you want to spend. And how strong you want your rear built.

And most guys who drag race, will tell you to take the sway bar off and throw it in the trash. If you want to keep it on the car, just keep the stock one, unless your going road racing.

Rangers had four lug? I thought they were 5?

Yes. That would be one of these fine animals...

http://www.americanmuscle.com/swarr-bar-88-rear-86-04.html

Hmm i like that... That will definatly be purchased!

SVTSkip

11-12-2008, 11:37 AM

Thought you might like it. The install is fairly simple, and the car I saw it tested on got a bit better off the line, but more importantly became MUCH more consistent !

Notch93

11-12-2008, 01:45 PM

Rangers had four lug? I thought they were 5?

No, never said anything about the ranger axles. I was refering to the 33 spline/spool setup.:patriot:

or you can go all out like I just did on my wifes car 33 spline axles full spool c-clip elem. cover and 1/2" studs. and a anti-roll bar it went from a 2.20 60' to a 1.20 60' just my 2 cents

nastynotchback1

11-12-2008, 02:05 PM

Cobra diff has carbon fiber disk in it.holds alot better

Notch93

11-12-2008, 03:20 PM

Cobra diff has carbon fiber disk in it.holds alot better

:yes1:

Thats what is going in mine, I have one that was taken out of a 04 Cobra with 500 miles.

You can get the same piece new for $249.00.

http://www.buyfordracing.com/shop/product_info.php?products_id=543cPath=3_37

MustangCRZY302

11-12-2008, 10:09 PM

No, never said anything about the ranger axles. I was refering to the 33 spline/spool setup.:patriot:

Ah ok gotcha. Yea that is definatly an option.

Cobra diff has carbon fiber disk in it.holds alot better

It fairly easy to find one? Or easier to just buy a new one?

Notch93

11-12-2008, 10:25 PM

It fairly easy to find one? Or easier to just buy a new one?

They are out there, just make sure you know the one your getting is good. Because the rebuild kit with the fiber clutch plates is $100.00.

MustangCRZY302

11-13-2008, 01:44 PM

They are out there, just make sure you know the one your getting is good. Because the rebuild kit with the fiber clutch plates is $100.00.

Very true. I'll have to keep an eye out for one! If not, that link ya posted for the new one is where I'll go. Thanks!

BDASPNY

11-13-2008, 01:59 PM

Very true. I'll have to keep an eye out for one! If not, that link ya posted for the new one is where I'll go. Thanks!

the one going in my car has the carbon fiber clutchs. i bought it brand new the price was not much more so i figured why not.

Silver91Hatch

11-13-2008, 06:06 PM

Can you install the fiber disc's in a factory explorer/truck diff???

Notch93

11-13-2008, 06:13 PM

Can you install the fiber disc's in a factory explorer/truck diff???

Yes :yes1:

8.8 INCH TRACTION-LOCK REBUILD KIT WITH CARBON DISCS

� Kit includes carbon fiber clutch pack, shims, S-spring and instruction sheet
� Fits all 8.8" Traction-Lok differentials
� Carbon fiber discs designed for higher torque usage
� Used in 2003-04 and 2007 SVT Mustang Cobra

http://www.buyfordracing.com/shop/product_info.php?products_id=609cPath=3_37

MustangCRZY302

11-13-2008, 08:32 PM

the one going in my car has the carbon fiber clutchs. i bought it brand new the price was not much more so i figured why not.

Cool, where did ya get it from?

Silver91Hatch

11-13-2008, 10:29 PM

I will find out my price from work on the factory 03/04 cobra stuff, bound to be less than $100.

Notch93

11-13-2008, 10:51 PM

I will find out my price from work on the factory 03/04 cobra stuff, bound to be less than $100.

The diff, or the rebuild kit? Because your cost will be more then $100.00 on the diff.:yes1:

Silver91Hatch

11-13-2008, 11:03 PM

Just the rebuild kit. I got 4-5 31 spline trac-locs but they do or will need clutches, 03/04 is something to think about.

Notch93

11-13-2008, 11:24 PM

Just the rebuild kit. I got 4-5 31 spline trac-locs but they do or will need clutches, 03/04 is something to think about.

:thumbsup1:

Notch93

11-14-2008, 07:25 PM

This a hell of a deal.:yes1: And they are in NC.

33 spline axles,spool,long studs

c-clip elims pressed on...for fox body with drum brakes...

$350

http://www.clickclickracing.com/forums/showthread.php?t=7241

Fox84

11-25-2008, 04:17 PM

Is there anyway to tell what spline axles you have without pulling them ?My car was upgraded to a 8.8 with 430 gears before me. It's still 4 lug. I noticed it leaving only one set of marks so I need do something soon. Will the 03 04 Cobra diferentials fit early model 8.8's?
Barryb

nastynotchback1

11-26-2008, 12:04 PM

is there anyway to tell what spline axles you have without pulling them ?my car was upgraded to a 8.8 with 430 gears before me. It's still 4 lug. I noticed it leaving only one set of marks so i need do something soon. Will the 03 04 cobra diferentials fit early model 8.8's?
Barryb

you have to pull them to know and yes the diff will fit.

Fox84

11-26-2008, 07:24 PM

Talked to the local guru of rears today to get a price on rebuilding my diferential. He said adding a extra clutch over stock would greatly help my launch and he suggests upgrading to the 31 spline axles and eliminate the c clips. I also wanted a price just for the install of the new clutch kit. With the info I've read here I should be able to make the right choice or just do it myself!
Barryb