Help Me decide what to do for slip'n posi unit?

[timfoster405]

Quick question... my 2007 only has 17k miles. I have only run it at the track on DR's about 8 times...my best run was today on a 12 psi pulley.

11.05 sec at 122 mph w/ a 1.60 60 ft.

While doing the burn-out, I had only one tire spinning. I went ahead anyway and ran my best run to date.

My rear is completely stock w/ 3.31 gears.

Does this mean my posi unit is trashed? worn out?

On the street, I can get both wheel spinning not problem and when I left the line today, I did not spin at all... very clean launch from about 2000 rpms w/ my auto.

Bottom-line, what does it take to wear out a factory posi unit? Is my hp level too much for the factory posi unit?

Lastly... is the carbon disc re-build kit any good? or should I just get an Eaton unit?

thanks,

 

[skwerl]

You can try adding a little more friction additive first and see if that helps. Will cost less than $10 and won't hurt anything if it doesn't help. Next step would be to pull the cover and take a look. If it's shot then look at other options like the Eaton Truetrac. It's a worm gear design with no clutches so it won't ever wear out.

 

[timfoster405]

who sells the friction additive?

 

[skwerl]

Any auto parts store. I saw it at Advanced Auto for $8.00.

 

[TexasBlownV8]

Recently replaced the clutch packs in mine; a few clutches were badly worn. I opted for the carbon fiber clutch packs which cost a little more. The kit has all you need, except for fluids and friction modifier.

For friction modifier, I stick with the Motorcraft brand, XL-2 or the other one. The local "A-Line" auto parts carries the 4 oz bottle for under $5.

 

[Mustang30212]

With mileage that low and so few passes...I'd be more inclined to think that maybe you just didn't have enough water on the wheels to get them both spinning at the same time.

Just a thought.

RH

 

[skwerl]

I've heard they sometimes need to be 'reset'. Find an empty parking lot and do some slow speed figure 8s. If it doesn't help then it cost you nothing to try.

 

[timfoster405]

With mileage that low and so few passes...I'd be more inclined to think that maybe you just didn't have enough water on the wheels to get them both spinning at the same time.

Just a thought.

RH

I think you are correct. My launch was pretty hard and I got no spin whatsoever...my 60' was 1.60. I held about 2000 rpms and FLOORED it.

The track was prepped pretty good too. A buddy of mine in a 11.50 sec Buick Turbo had a hard time doing a burn-out too.

On the way home...I lit them both up fine. I need to get gears...from 3.31's to 3.73's and I think I am going to use the carbon faces upgrade kit for $100.

 

[Swarzkopf]

Friction modifier will make the clutches slip MORE, not less. If you've got one-wheel-peel going on, adding friction modifier will just make it worse.

 

[Turbostangs90]

Recently replaced the clutch packs in mine; a few clutches were badly worn. I opted for the carbon fiber clutch packs which cost a little more. The kit has all you need, except for fluids and friction modifier.

For friction modifier, I stick with the Motorcraft brand, XL-2 or the other one. The local "A-Line" auto parts carries the 4 oz bottle for under $5.

This, you can find the instructions online and can be done in a day. Alot cheaper than a posi unit and it works!

 

[timfoster405]

According to Latemodelrestoration's website, these upgraded carbon faced clutch discs came as factory stock in "2003-2004 Cobra 2005-13 Mustang GT, & 2007-12 GT500" which includes my 2007 Mustang GT.

Therefore, my car already has these carbon fiber clutch pack...allbeit potentially worn out...can anyone verify this?

goto:

http://www.latemodelrestoration.com...88-Traction-Lok-Rebuild-Kit-with-Carbon-Discs

 

[skwerl]

Friction modifier will make the clutches slip MORE, not less. If you've got one-wheel-peel going on, adding friction modifier will just make it worse.

You have that backwards, my friend.

 

[Whiskey11]

With mileage that low and so few passes...I'd be more inclined to think that maybe you just didn't have enough water on the wheels to get them both spinning at the same time.

Just a thought.

RH

FWIW I think it would depend on how those miles are done. I had mine rebuilt at approximately 30k miles and the tech that did the work told me that the clutch pucks were basically just the metal disks with ZERO friction material left. I didn't get to see them but I trust him as he is a friend of mine. Granted, 2 years of autocross will do that to a diff, especially one as nearly worthless as the Traction-Lok units are. The next time it goes open on me I plan on replacing it with something that wears out much slower like a Wavetrac which should last a heck of a lot longer!

 

[Mustang30212]

[PHOTOB][/PHOTOB]

According to Latemodelrestoration's website, these upgraded carbon faced clutch discs came as factory stock in "2003-2004 Cobra 2005-13 Mustang GT, & 2007-12 GT500" which includes my 2007 Mustang GT.

Therefore, my car already has these carbon fiber clutch pack...allbeit potentially worn out...can anyone verify this?

goto:

http://www.latemodelrestoration.com...88-Traction-Lok-Rebuild-Kit-with-Carbon-Discs

Not so sure on the 05-10's...but I did read that the 11's and up had them as well as the Shelby's and the Cobras.

RH

 

[rayS197]

My clutches went out @ 5k. If you have the funds, while doing the gears it makes sense just to get the TruTrac. Carbon fiber clutches are just that (another set of clutch packs) and a band-aid fix. JMO.

 

[Swarzkopf]

You have that backwards, my friend.

Nope. Friction modifier is what allows the clutches to slip. Adding more of it will make them slip more.

 

[rojizostang]

my 07 had carbon fiber

 

[fdjizm]

Save future repair money and get a trutrac, my stock stuff was one wheel peeling at around 25k. would have been just a little less to repair my stock shit and wait for it to break again or put a trutrac in and forget about it... chose trutrac!

 

[Mike K]

Just weld the gears and be done....jk

Get a trutrac