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All 79-04 Ford Mustang 7.5" & 8.8" Rear Ends carried 28 spline Rear.

The V6 Cars came with a Open differential and the Gt, Cobra, Mach 1 came with limited slip differential.

The 03/04 Cobras also have a limited slip differential but comes factory with carbon fiber clutches.

All 79-93 Ford Mustang 7.5" & 8.8" Rear Ends were 4 Lug and Drum Braked w/ 4 x 4.25" Bolt Pattern

All 94-04 Ford Mustang 7.5" & 8.8" Rear Ends were 5 Lug and Disk Brake w/5 x 4.5" (OR 5x114.3mm) Bolt Pattern.

ALL 79-93 Rears Used 29.25" Length Axles.

ALL 94-98 Rears Used 29.93" Length Axles.

ALL 99-04 Rears Used 30.62" Length Axles.

All 94-04 V6 GT COBRA MACH 1 28 SPLINE Axles will swap out between the correct length 7.5" or 8.8" Rear.

7.5" and 8.8" Rears all shared the same exact axle ( Year Specific)

All 1979-98 AXLE LENGTHS ARE THE SAME, They are the same exact Housing!

For Ex. I have a 1986 8.8 Rearend, with 7.5" Housing ends from a 94-98 And im running 94-98 V6 Axles.

So the only difference between the FOX Rear and the Early SN95 Rears are the AXLE ENDS and Axle Length.

The V6/Gt etc. All share the same AXLE BEARINGS and AXLE SEALS!!!

All Stock 28Spline 7.5" or 8.8" Rear End Carrier Cross Pins are the same size, 3/4" Pins.

These Cross pins hold spider gears together and Commonly get replaced when replacing rear gears.

To lock the cross pins in place and keep them from backing out a cross pin bolt is used.

This bolt is easy to remove using a 8mm or 5/16 6 point wrench. Can use a 3/8 rachet with swivel aswell.

But there is litle room with Right side cap still on. Or if your tearing the rear down just remove the cap first.


Anti-lock brakes (ABS) were optional on the newer model mustangs so some rears have ABS rings and some won't.

SRA rears have there own style ABS Sensors and the IRS Sensors were IRS Specific.

1994-04 Cobra, 2001 Bullitt and 03-04 Mach 1 All shared a Outer diameter 11.65" (295.9mm) Rear Rotor.

With this came Increased initial “bite” and greater stoping power.

1994-2004 V6 and GT all shared a Outer diameter 10.51" (266.95mm) Rear Rotor.

Not as much stoping power as a cobra brake setup but it gets the job done for most.


Calipers interchange from 94-04 SRA or IRS, V6 GT COBRA MACH 1 and BULLITT.

Confused? Don't be...

The only thing that changes when upgrading to the larger rear breaks is a larger rotor and i taller caliper bracket.I have had quite a few rears in my own car SRA and IRS and have always kept the same rear calipers on each rear with no issues.

Rear Calipers use "Twist" in style pistons, they won't compress like the fronts with just a simple c-clamp.

Note: They sell a special tool for this!

Since most of us don't have the tool, you can use a nice pair of channel lock pliers to grip the outside edge of the piston to twist it in. Be carful not to catch the boot and tear it.

To help push the piston in while you twist you can put a c-clamp in the front of the pisting with light pressure to help assist the piston going back into the caliper.

The 94/95 Mustangs Has the brake lines hard lined on the actual rear just as the fox body cars.

They had 1 rubber line that went to a break line block straight above the center of the differential.

Then in 96-04 The brake lines were hard lined on the car out to the wheel wells and there is a bracket where the rubber line mounts for the caliper.

The IRS cars were also the same as they were produced from 99-04 But the actual caliper brake line/hose was very different.

All SRA cars 96-04s are able to use V6 or GT etc. caliper lines and they all swap out with no issues.

But the IRS cars are IRS specific. So remember this when swapping in a IRS you might need to pick up a few break lines.

NOTE: You can get away with the 96-04 V6 or GT etc. stock caliper lines on a IRS car only if you remove the mounting bracket and allow the lines to hang.I did this on my car and it worked fine with no issues and now wit the SRA back in the car i bolted them back in place like nothing ever happend.

Bolts/Hardware Torque & Tech

-Differential cover bolts 1/2" 6 Point

-Pinion shaft lock bolt 15-30 lb-ft 8mm/ 5/16 6 Point

-Pinion Nut 1-1/16th" 6 Point

-Ring Gear Bolts 19mm

-Main Cap Bolts 19mm

-Center section main caps torque to 70-85 ft. lbs.Be sure to install the caps with the triangles pointing outward.

-Using something to hold the pinion flange, tighten the pinion nut to 160 ft/lbs (Is a real PITA)

-Using an inch-pound torque wrench, frequently measure the pinion bearing preload while getting it tight.

it should be 8-14 inch lbs. (0.8-1.6 Nm) for used bearings or 16-29 inch lbs. (1.8-3.2 Nm) for new bearings.

-When setting the back lash used a dial indicator, measure off the ring gear and backlash should be 0.008-0.015 in. With new gears try to keep it as close to 0.008 as possible as they will break in, i like to do used gears around 0.010-0.012.

- Aso make sure bearing caps are torqued to the correct torque specs before you check the backlash.

-Lugnuts 85-105 lb-ft 19mm/21mm

-Driveshaft 70-95 lb-ft 12mm (12 Point)

-Ring gear fasteners 70-85 lb-ft (in stages, Start at 40 ft/lbs and work your way up)

(SRA = Straight Rear Axle)

(IRS = Independent Rear Axle)

Been working on this for a bit tonight and i figured its good enough to post up for now but is not done.

I would still like to come back ad some additional info soon. If you have any thoughts or ideas with some more info that you think belongs in this thread please feel free to PM ME!

Thanks -330

Edited by 330CubeGt
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