I did a HPDE at Pikes Peak International Raceway a few weekends back (will post pictures when I get the chance) and a day after in my garage there were several spots of dripped oil or grease under the right rear axle.

At first I thought it was I put too much grease in the zerks on my Steeda LCAs and BMR billet endlinks, but today finally got to slide under and see that it came from the axle itself. It sprayed a fair amount of, I assume, differential fluid over the right rear suspension, coated my Pypes axle-back tube, and ruined the exhaust tip (which already looked crappy and will be replaced soon).

There's an odd 1" high and 3/4" nipple looking thing on the topside of the right rear axle (pointed up towards the body), halfway between the bellhousing and the brake/spindle that's not on the left side axle half, and it has a cap or something on top of it that spins freely, while a bolt or nut sits directly underneath the cap and feels screwed or welded to the axle itself. I'm pretty sure all the fluid came from this thing.

Anyone know what it is and if this means it's defective??

 

well it sounds like it was not over filled but that the nipple was loose and the cornering may have made it spill out..... i know from the factory mines was over filled and it was EVERYWHERE!...... make sure the levels are good and make sure that nipple you see is not loose

 

Although I believe that's the breather/check valve, a pic is worth 1000 questions. In the case it's the check valve, yes, it seems to be defective. It's supposed to let air in and out as the axle heats up, but not fluids. Sounds like it's broke... at first read, of course.

*shakes fist at Polo*

 

I can try getting a pic, but I can barely even see it when the car is up on jack stands, it was more by feel than anything. I would think breather/check valve is right, though, as the top piece that spins around freely seems like it would allow air in/out.

So if it's letting fluid out, should I just tighten the nut at the base of it? I didn't try cause I didn't know what it is. Probably be a bit difficult to get a wrench there, too, though I guess letting the axle go to full droop would make it easier.

Or should I just head to the dealer? I'm concerned they'd ask how it happened, and being on a track they probably wouldn't cover it. Could just say I was in the mountains, though, there's tight enough curves there to cause it, I'd guess.

 

It's a breather, the leakage is normal under hard cornering. I have a catch-can rigged up for mine, as do our Roush Track Pack racers. I think even the guys from Rehagen that post on here use catch cans.

Nothing to worry about, just get a catch can rigged up (we like old Dasani bottles ), and check your diff fluid level.

 

Ah, so it's a 'don't do that' issue... unless you mod it. Got it. Kewlies.

/off to remember to get a mod for that... just in case.

 

Cool, good to know.

So how do you go about doing those two things?

Especially the catch can, I really can't imagine getting something to stay on the axle during hard cornering...

Unless you're saying just under the spot in the garage? What about the overflow and soiling my otherwise perfect () undercarriage??
(I've seen TacoBill's pics. I don't drive mine in snow or even rain much, but still, can't imagine keeping it that clean)

 

Here's the one they used on the KR, which looks to have a robust mount... but as expected, it is a bit a pricey at $129

http://www.shelbystore.com/product-p/tkr1.htm

 

Very nice piece, glad I'm not the only one that's had this problem.

Would the leaking itself indicate the differential was a touch too full?

Wondering if I should wait and see if this happens again before coughing up the dough for this reservoir.

 

No, I'm talking about for on-track use and also normal DD'ing
If you're doing the "20oz water bottle" one, you zip tie the bottle upright in the "pocket" behind the pass side gas tank. Unfortunately, I don't have a picture But with the bottle oriented almost completely vertical, there is little/no risk of fluid leak during hard cornering. To make this work, you have to rip the cap off of the breather (there is the cap, a spring, and a small washer/gasket that will be removed), and attach a hose to remaining bung using a small hose clamp. Just make sure to leave enough slack in the hose for it to move w/ the axle.

Only "problem" with this is that the fluid doesn't auto-drain back into the diff via gravity, so you'll have to empty the catch bottle and re-fill the diff if necessary by hand. Our race car had about 8-10 oz in the catch can after about 35-36 practice/race sessions.

Whoa, pricey, but functional...I might look into this in 2010. The gravity-drainback feature is nice. Any idea where this bolts up? I'm guesing we are looking at the "bottom" of the unit if it's a gravity drain...

 

Cool idea, but I'm surprised at the volume you get! How much is in the differential, anyhow?

There's an install doc on the Shelby site, says it bolts to the R side upper third link body mount and the gas tank straps. Looks fairly simple.

I'm thinking I might do this next year, too, as I don't like all the splattering I had -- it even got into my right rear wheel, likely some permanent staining cause I didn't realize it for a while. And the idea of dropping that on the track,

 

I can guarantee you, if you're going to keep putting the car on-track, it WILL happen again.

 

Well, you convinced me then. Gonna pick up that reservoir sometime over the winter.

Don't know what I'd do without The Mustang Source. Probably spend a lot more time at the dealer leech!

You guys rock

 

if you have the time you could probably make one on your own as stated above. If you know a welder even better.

 

So what's up?!? That link now goes to a page that says 'you need a password to see this'.

They better not be making us get the Shelby membership ($50 for the year) to buy these.

Strange how it changed so soon after the link was posted here. I'm gonna get in touch with them and see what's up.

 

http://www.shelbystore.com/product-p/8r3v-4022-kr.htm

 

Nice work.

 

Just ordered mine

 

I said "screw it" and ordered one today. Upcoming bonus money is already burning a hole in my pocket

 

Must have been that thin air in CO!

I never noticed mine leaking on track days, hmm, maybe I need to drive it harder!