2003 rear end.

Swapping a coyote into a 89 original 4cyl hatch. Don’t want to spend 4 grand on a moser build to order. MPS auto salvage has some rear ends for $500 from a 2003. It has a 3.27 rear gear that will work fine with my 6r80. Also wanting to run the SVE Series 3 wheels. 18x10 285/35/18 tires in the kit from LMR. Will this rear end bolt up to my fox and work with these rims and tires? What modifications will I have to make? Thanks!
 
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Ideally a 94-94 rear end would be more ideal.


Two reasons why 99-04 rear ends are not. Ford changed the LCA bolt sizes in 1999 to a 14’m bolt from a 12mm bolt on the 86-98 housing.

Bigger issue is the width. The engine housing changed width in 1999. It’s now 1.5” wider than a 86-98 rear axle, so when you add on the disk brakes you gain 1.5” each side over a standard 86-93 fox body with drum brakes.

At least with a 94-98 axle, you only gain 0.75” each side and you can buy offset brackets and axles to bring the at back in to fox body width.

Once thing I’ve suspected by never confirmed is the offset brackets on the 99-04 axle, with 94-98 axles shafts might bring those wheels in 0.75”. But then you are still stuck with an additional 0.75” over an 86-93 drum brake rear.

It makes wheel selection tricky.
 
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Ideally a 94-94 rear end would be more ideal.


Two reasons why 99-04 rear ends are not. Ford changed the LCA bolt sizes in 1999 to a 14’m bolt from a 12mm bolt on the 86-98 housing.

Bigger issue is the width. The engine housing changed width in 1999. It’s now 1.5” wider than a 86-98 rear axle, so when you add on the disk brakes you gain 1.5” each side over a standard 86-93 fox body with drum brakes.

At least with a 94-98 axle, you only gain 0.75” each side and you can buy offset brackets and axles to bring the at back in to fox body width.

Once thing I’ve suspected by never confirmed is the offset brackets on the 99-04 axle, with 94-98 axles shafts might bring those wheels in 0.75”. But then you are still stuck with an additional 0.75” over an 86-93 drum brake rear.

It makes wheel selection tricky.
Thanks for the quick reply! MPS also has some for a 95 for the same price. Just looking at a gear change with those ones. Might go that route.
 
Swapping a coyote into a 89 original 4cyl hatch. Don’t want to spend 4 grand on a moser build to order. MPS auto salvage has some rear ends for $500 from a 2003. It has a 3.27 rear gear that will work fine with my 6r80. Also wanting to run the SVE Series 3 wheels. 18x10 285/35/18 tires in the kit from LMR. Will this rear end bolt up to my fox and work with these rims and tires? What modifications will I have to make? Thanks!

I strongly recommend the $4k Moser rear end. It completely changes the car.

Kurt
 
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I think he just wants to save the cost of doing a 3.27 year install by buying an axle already equipped.

Granted there is no garantee the limited slip is still functional after 20 or so years of who knows what sort of driving
 
Some 94-98 rears did come with 3.27s. I believe it was an option for automatics. Should be an axle tag that will tell the factory gear ratio. Who knows if they were swapped out.
 
Honestly, I wouldn’t bother with a 99+ 8.8 unless you plan on narrowing it.

98 and older mustang 8.8 rears come up for sale somewhat regularly, I’d hold out for one of those instead. You can convert to a 9in for much cheaper than it costs to have a fabricated 8.8 done, but those moser 8.8s do look sweet.
 
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Why not just a 89 GT 8.8 axle
5L5 is on it.. and Kurt what changes so drastically? To make it worth 4k?
To me those 88's are cheap everywhere and easy to fix
I was skeptical at first, I thought it was too much money, and then just went for it. It's the best mod I have ever done. It completely changes the car. It gets more weight on the rear of the car just for starters. The Eaton truetrac differential is out of this World (you have to do a bolt in style axle to use an Eaton differential, that's why it costs $4k). At almost 600hp, the car will accelerate in first gear, not burn the tires down, and will dead hook in 2nd gear. You can put the throttle down in the corners, and it won't fish tail. It's much closer to having a modern muscle car than having an old muscle car. The factory differential and axle sucked with the stock 235hp engine; going to a 400+ hp Coyote without updating the drivetrain to match just makes the car that much worse. I am having the same argument with a close friend of mine. He is buying a brand new Ford Coyote crate engine.......at whatever the hell that costs, and then putting together and axle with hodge podge parts. He'd been better off spending the $4k on a Moser axle, and getting a junkyard Coyote engine. Modify your car equally across the components. Doubling the engine power without doubling the ability of the axle is going to leave the car as strong as it's weakest link.

Kurt
 
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I was skeptical at first, I thought it was too much money, and then just went for it. It's the best mod I have ever done. It completely changes the car. It gets more weight on the rear of the car just for starters. The Eaton truetrac differential is out of this World (you have to do a bolt in style axle to use an Eaton differential, that's why it costs $4k). At almost 600hp, the car will accelerate in first gear, not burn the tires down, and will dead hook in 2nd gear. You can put the throttle down in the corners, and it won't fish tail. It's much closer to having a modern muscle car than having an old muscle car. The factory differential and axle sucked with the stock 235hp engine; going to a 400+ hp Coyote without updating the drivetrain to match just makes the car that much worse. I am having the same argument with a close friend of mine. He is buying a brand new Ford Coyote crate engine.......at whatever the hell that costs, and then putting together and axle with hodge podge parts. He'd been better off spending the $4k on a Moser axle, and getting a junkyard Coyote engine. Modify your car equally across the components. Doubling the engine power without doubling the ability of the axle is going to leave the car as strong as it's weakest link.

Kurt
I have never heard of that particular axle but I am old and slow. So what makes it hook up so much better than say a 4 link? Does it bolt into a mustang using the stock arms or ? You have one in yours send me a pic of it so I can see what is so cool too.
 
Honestly, I wouldn’t bother with a 99+ 8.8 unless you plan on narrowing it.

98 and older mustang 8.8 rears come up for sale somewhat regularly, I’d hold out for one of those instead. You can convert to a 9in for much cheaper than it costs to have a fabricated 8.8 done, but those moser 8.8s do look sweet.
Yes you can
DSCF0734.JPG
 
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A friend got a 8.8 trac loc unit and axles from a explorer, they have 31 splines, had the axles shortened to fox length added NRC brackets to a 96 housing and BAM, a very stout, inexpensive 8.8 with disc brakes.
Not as fancy as the Moser but he says there is something wrong if you're looking at his rear end :confused:
 
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I have never heard of that particular axle but I am old and slow. So what makes it hook up so much better than say a 4 link? Does it bolt into a mustang using the stock arms or ? You have one in yours send me a pic of it so I can see what is so cool too.

So it's not a particular axle per say, it's a factory axle modified. So it bolts up just like a factory axle with whatever suspension system you have. You won't see much from the pictures, but I will link my build thread which has pictures. I had my factory axle modified actually. Moser offers the M88 axle which is a new casting of a factory axle modified anyway you want it. In the end, I spent more money, and dealt with way more hassle than just buying a Moser M88 axle, so that's how I would go. So the largest mod is the transition to what is called a bolt on axle, or "9 inch ends." This is massively important for drag racing on slicks. Slicks are really hard on the drivetrain, and snapping an axle is common. The 8.8" axle has design flaw, the axle is secured inside the differential with a C-clip. So if the axle brakes, there is nothing holding the wheel on the car, the wheel can eject from the vehicle, and you have a nasty crash. The old 9" design secures axles at the wheel, so if the axle brakes, the wheel stays on the car. The old 9" also has a much larger, and more durable wheel bearing in it. Moser makes an axle end that has the full size bolt on size 9" bearing, but has an 8.8" bolt pattern for brake compatibility.

The second part of the build has to do with the differential. The factory Ford T-loc differential is just a piece of :poo:, I mean there is no way to sugar coat it. It's the reason Mustangs spin tires and fish tail so much. Basically, one tire starts spinning long before the differential locks up, and the other tire starts spinning after it locks up because the car is not accelerating, because the first tire is in kinetic friction, not static friction. Obviously on a pure drag car you would have a spool, which is the absence of a differential, but on a street car, the Eaton True-trac, or Strange S-trac can simulate it really well while maintainging differential capabilities for turns. It's this torque based management friction thing that I don't understand, but my Dad could if you had 2 hours to listen to him explain it. Anyway, being able to put a better differential in makes a huge difference.

The true-trac differential can not be used with a C-clip design, because there is no provision in the differential for the C-clips. It's quite simply impossible to fit them in. However, you can secure the axles at the ends using something called a C-clip eliminator kit. It's a bolt on kit you can do it at home that requires to cut the end of the axle off. It's a non precise cut you can do with a hack saw. It's way cheaper than welding on new ends, and totally a realistic option. The downsides to it are: It uses a smaller less durable bearing that has a tendancy to fail. They also tend to leak gear oil. It also does not correct any factory axle imperfections. Factory axles tend not be straight. It's not uncommon for the wheel base to be off by 1/4" from side to side. Mass produced axles just aren't straight. It's the reason Mustangs have to have thrust angle alignments. When you go to a weld on axle end, the axle is jigged on a straight bar, and all factory mis-alignment is corrected by welding the axle end on at the correct angle.

Build thread

Kurt
 
Good to know about that axle and you are absolutely right on the rest of that too. I am running a pile trac loc too just because I got it free for my 9 inch. Very much hate replacing those wheel bearings and I have replaced a bunch. Going to buy the 400.00 axle bearing tool when I need to do mine again. I like the looks of that housing with the arm mounts welded on. You have the 33 spline? Thanks for the info
 
So it's not a particular axle per say, it's a factory axle modified. So it bolts up just like a factory axle with whatever suspension system you have. You won't see much from the pictures, but I will link my build thread which has pictures. I had my factory axle modified actually. Moser offers the M88 axle which is a new casting of a factory axle modified anyway you want it. In the end, I spent more money, and dealt with way more hassle than just buying a Moser M88 axle, so that's how I would go. So the largest mod is the transition to what is called a bolt on axle, or "9 inch ends." This is massively important for drag racing on slicks. Slicks are really hard on the drivetrain, and snapping an axle is common. The 8.8" axle has design flaw, the axle is secured inside the differential with a C-clip. So if the axle brakes, there is nothing holding the wheel on the car, the wheel can eject from the vehicle, and you have a nasty crash. The old 9" design secures axles at the wheel, so if the axle brakes, the wheel stays on the car. The old 9" also has a much larger, and more durable wheel bearing in it. Moser makes an axle end that has the full size bolt on size 9" bearing, but has an 8.8" bolt pattern for brake compatibility.

The second part of the build has to do with the differential. The factory Ford T-loc differential is just a piece of :poo:, I mean there is no way to sugar coat it. It's the reason Mustangs spin tires and fish tail so much. Basically, one tire starts spinning long before the differential locks up, and the other tire starts spinning after it locks up because the car is not accelerating, because the first tire is in kinetic friction, not static friction. Obviously on a pure drag car you would have a spool, which is the absence of a differential, but on a street car, the Eaton True-trac, or Strange S-trac can simulate it really well while maintainging differential capabilities for turns. It's this torque based management friction thing that I don't understand, but my Dad could if you had 2 hours to listen to him explain it. Anyway, being able to put a better differential in makes a huge difference.

The true-trac differential can not be used with a C-clip design, because there is no provision in the differential for the C-clips. It's quite simply impossible to fit them in. However, you can secure the axles at the ends using something called a C-clip eliminator kit. It's a bolt on kit you can do it at home that requires to cut the end of the axle off. It's a non precise cut you can do with a hack saw. It's way cheaper than welding on new ends, and totally a realistic option. The downsides to it are: It uses a smaller less durable bearing that has a tendancy to fail. They also tend to leak gear oil. It also does not correct any factory axle imperfections. Factory axles tend not be straight. It's not uncommon for the wheel base to be off by 1/4" from side to side. Mass produced axles just aren't straight. It's the reason Mustangs have to have thrust angle alignments. When you go to a weld on axle end, the axle is jigged on a straight bar, and all factory mis-alignment is corrected by welding the axle end on at the correct angle.

Build thread

Kurt
I’m never really the biggest fan of c clip eliminators. I’ve seen them be hit of miss as far as sealing goes, and after we had one of the bearings go out and damn near lost a wheel with one- I can’t see myself doing that again. Honestly most people won’t ever break something like a 31 spline axle, they can really take a good beating with a somewhat lightweight car like a fox body. Also, if you want some extra insurance there’s always the disc brake option, which really should keep the wheel on the car if you have an axle break.

IMO it’s just tough to justify moser money, especially when you can send off a 8.8 housing to a company like trz, tin soldier, or others and have one beefed up with 1/4 tubes and 9in ends for 1/3 the cost.
 
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I’m never really the biggest fan of c clip eliminators. I’ve seen them be hit of miss as far as sealing goes, and after we had one of the bearings go out and damn near lost a wheel with one- I can’t see myself doing that again. Honestly most people won’t ever break something like a 31 spline axle, they can really take a good beating with a somewhat lightweight car like a fox body. Also, if you want some extra insurance there’s always the disc brake option, which really should keep the wheel on the car if you have an axle break.

IMO it’s just tough to justify moser money, especially when you can send off a 8.8 housing to a company like trz, tin soldier, or others and have one beefed up with 1/4 tubes and 9in ends for 1/3 the cost.
I wish I knew about cheaper options at the time. I ended up spending more money locally than I would have with Moser. The labor was $1600 alone. I have an SN with disk brakes, and I have seen more one make the falicy that the brake caliper is going to save you when the axle brakes. I just went right to the 33 spline axles.

Kurt
 
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I wish I knew about cheaper options at the time. I ended up spending more money locally than I would have with Moser. The labor was $1600 alone. I have an SN with disk brakes, and I have seen more one make the falicy that the brake caliper is going to save you when the axle brakes. I just went right to the 33 spline axles.

Kurt
As long as the axle breaks inbd of the bracket (which they usually do) then the disc should keep the axle from sliding all the way out. If you break an axle on a road course in a corner, it might be a different story. Like I said, it’s extra insurance if :poo: hits the fan.

I’m Definitely a fan of stuffing the highest spline count you can inside the housing.
 
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