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Took the car in today for the rear diff leak. There is not an actual tsb out for this right now. Figured something interesting out with the tech. We figure it's the heat from the exhaust that's actually melting the rtv and causing the leak. You can see the areas that have gotten hot and melted it. It would be interesting to see if everybody that has the problem has and aftermarket cb. We compared it to a stocker and it's definately 1/4 to a 1/2 inch closer to the pumkin. So, he's gonna fabricate a heat shield and coat it with some reflective paint on the side facing the exhaust and we're gonna see if this solves the problem. Anyone leaking with the stock cb?? Anyway, this is perhaps a new way to solve a old problem.
 

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Damn. That would be great if that fixes the problem. Shuldn't be too hard to fabricate something, would be interested to see pics of what ya'll come up with....
 

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sambandit said:
Figured something interesting out with the tech. We figure it's the heat from the exhaust that's actually melting the rtv and causing the leak.
That's awesome information, Sam. Thanks for sharing it, thanks for a great contribution to the community!

:salute
 

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Keeping external heat away is probably a good idea. I know the differential generates it's own heat, and quite a lot of it. I guess the 8.8 center section was really desgined to have axle tubes that would hold extra lube and that lube was distributed over a nice area ( the bottom of the axle tubes) to dissipate heat.

If you notice, the one thing Ford says you need to do to race an IRS cobra, is add a rear diff. cooler.

JT
 

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I'll bet going to higher gears the problem is even worse..
The 373,390 or 410's will be spinning a lot faster..
Is there a better fluid {differential } we can use.I know Ford recommends Synthetic.Is there a better(COOLER) running Fluid on the Market??
 

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I was told that the sealer that Ford uses is what causes 99% of the diff cover leaks.

Perhaps the heat is related to this issue? Maybe their sealer is not very heat resistant?
 

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If you crawl under and take a look the leak problem is obvious.
The rear cover is mounted solid to the chassis,however the front of the gear housing is mounted by 2 ears with flexible bushings on either side.
It shouldnt take a rocket scientist to see that the front portion is going to try to twist under torque while the rear cover remains stationary,this is obviously going to have some type of adverse effect where the 2 parts mate,loosening of bolts and eventual leaking.
possible fixes would include solid front mounts,or possibly drilling the rear cover and housing for dowel pins to limit the twisting effect.
Thats My Opinion..
 

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sn8kbite said:
If you crawl under and take a look the leak problem is obvious.
The rear cover is mounted solid to the chassis,however the front of the gear housing is mounted by 2 ears with flexible bushings on either side.
It shouldnt take a rocket scientist to see that the front portion is going to try to twist under torque while the rear cover remains stationary,this is obviously going to have some type of adverse effect where the 2 parts mate,loosening of bolts and eventual leaking.
possible fixes would include solid front mounts,or possibly drilling the rear cover and housing for dowel pins to limit the twisting effect.
Thats My Opinion..
I would have to say some thing else.

My friend SonicVenum from SVTPerf. got 4.10's & to this date he has no dif leak. I on the other hand have not changed it at all after i picked up my car from the dealer.....dif leaked & its FORD who is to blame......using the crappy Black Silicone Shit that wont hold up.

Went to SonicVenoms reffered shop XMP & no problems at all thus far.

FYI there is no Gasket being used on the Differentail Covers. Just Silicone.
 
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