BLEW ANOTHER *BLEEP* REAR END!!

To make a good suggestion, we HAVE to know more. So what are you breaking in the rear end? What kind of power and torque is the engine making? Is this an overheating problem, or a matter of not having lubrication where it needs to be in the hard corners?

It is common for drag racers to break axles and that is a simple matter of going to 31 spline axles with a matching limited slip differential. From what I've seen, an 8.8 with 31 spline axles and limited slip diff are a nice setup that can take LOTS of abuse. But this says nothing about long term durability and limited slip isn't ideal at tracks with corners. Back to road racing, what kind of differential are you running? From what I've read, most of the differentials that are good for road racing simply don't have the strength of the standard limited slip differential.

I recommend reading mustang performance handbook 2. While the book is older, it has a lot of great information on modifying the mustang to go road racing. Here is a brief summary of their suggestions: Add an extra vent on the left side axle tube. This allows off gases from the grease which is breaking down to escape instead of blowing seals. *my opinion... If the grease is breaking down that quickly, you should probably change it before every event, which can be easier if you buy a differential cover with a drain plug* The book also recommends one of 2 setups... installing 9" ford axle housings on the 8.8 rear end or purchase the Moser kit. The Moser kit would supply 2 stronger axles and 2 bearing carriers that are from a 9" ford housing. They state that this axle/carrier bearing has proven itself in millions of miles of racing, so it might just be your solution. I'm far from an expert on the road race stuff, but hopefully that gives you some ideas of what to research.

What about your competitors? What kind of setups do they run successfully?

RoadRaceGT said:

I just blew my third rear end in the last six months. 8.8", 3.90 gears, that's all I'm going to tell you guys for now.

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...8.8", 3.90 gears, that's all I'm going to tell you guys for now...

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Why the secrecy? If you want help, spill the beans.

What are you breaking? Spider or side gears? Taking teeth off the ring and/or pinion? Axles? Is the differential no longer "limited slip"? Bearings going?

When did it break? What were the conditions and what were you doing at the time?

Apparently you road race: Are you cooling the differential fluid?

What sort of power do you make? I presume it's a stick (live) axle but perhaps not: Have you got a Cobra IRS swap?

What's your budget?

Need more info.

Generally speaking, the 8.8 is pretty stout. The 28-spline axles can be swapped for 31-spline parts if you also change out the diff carrier. You might consider going to the carbon-fiber clutch packs from the Cobra Traction Lok (FRPP M-4700-C) though there might be better LSD options out there. I also think for road racing fluid temperature management is crucial: All the best parts in the world will not last if the fluid breaks down. A differential fluid cooler is a must if you're serious about extended road-race competition.

Several good points above. I have to agree that more information will make for a better answer.

But..... Just wondering why if $$ were not really a factor and the OP wanted a "nearly indestructable rear end", why wouldn't a road race Ford 9" be the ticket?

I would also have to agree that for serious road racing, a diff oil cooler would be needed especially if evidence of failure due to oil break down/over heating was noted.

Perhaps a different Limited Slip arrangement? The LSD in a Ford 8.8 is basically a friction device. Friction = heat.

Ford 9-Inch Rear Axle - Mustang Monthly

Currie Enterprises Rear End Sample Fox Body Style

Strange Engineering

wmburns said:

But..... Just wondering why if $$ were not really a factor and the OP wanted a "nearly indestructable rear end", why wouldn't a road race Ford 9" be the ticket?

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Good point. Maybe weight? Maybe class rules prevent it?

But if allowed it's a great idea. He could even have a couple of pumpkins with differing ring and pinions set up and swap the most appropriate one in for the track that day...

A lot depends on just how serious a road racer he is I guess. If his car sees track time 3 times a year with some buddies at the same local track, that probably calls for a lesser approach than if he competes around the state or country at different tracks, trailers the car there etc etc.