When are the breaking points of a stock 8.8

[ChuckyRick]

Searched and couldn't find any definitive answers, so here we go.. Taking the rear end out of the car this winter to have the axle tubes welded and some mild bracing done at a local race shop. At this point the car has almost 190k km's on it (i think that's around 116k Miles), So i'm going to be grabbing a master rebuild kit to freshen everything up and going to throw a LPW or TA girdle on it.

I guess my question is what's the failing point of the factory Traction-Lok and factory 31spl axles? Car will be making around 500whp when the rear end is installed again and will be staying at that point for awhile. It'll be 95% on street tires and 5% on DR's, it'll never see full on slicks. Will i need a new differential at this hp level on DR's or can i just put some fresh clutch packs in the T-lok? Same goes for axles, most breakage happens off the line with good track prep from what i can tell, So would i be okay if just running DR's on the street?

If you guys do think i should upgrade, What's everyone running? Are the spring clutch style units from Eaton, Yukon, Auburn, etc holding up to the abuse or should i spring for a TruTrac or something similar? Also are the Moser axles worth the extra $100+ or would i be fine with another brand like TENfactory, Alloy USA or Strange?

Alot of questions i know guys, But finally.. if you guys have any other input on what should be done to my rear end while i have it out rebuilding it i'd greatly appreciate it thanks

 

[stkjock]

There never is a 'magic number' to these questions.

The stock axles are holding up in my car. The stock diff lived at 900+ whp for a time
I'd upgrade to a GT500 diff or trutrac in your situation if it were me

 

[fdjizm]

Spider gears, when you start doing one wheel peels after those shitty clutch packs give up the ghost.
I've been running a trutrac for quite a while (as have many others) and it hasn't let me down.
Haven't heard anything bad about the axles at all, stock are very stout.

 

[NickD87]

Don't get alloy USA axles, I bought a set the machining is junk and the bearings and seals leak.
Ended up replacing with what I was told was a NTO gt500 rear end (I have my doubts) repeated launches on radials in a stick car (best of 1.56 60') and rear end is fine. Welding the tubes and Moser or strange axles is a great idea, I'd get the gt500 clutch upgrade kit for the diff and leave it. It's mostly a street car it sounds like so then you have no compromises

 

[Coosawjack]

Sticky tires and 500 RWHP in one of these!!

 

[Pentalab]

The eaton tru-trac comes in 2 x versions.

http://www.vmpperformance.com/Eaton-31-Spline-TrueTrac-Differential-for-05-14-8-p/dts-913a561.htm Uses oem 31 spline axles. 3 x pinions per side. This is what most folks use. Superb for dd street and strip use and also road course /auto cross. 3.5:1 bias ratio. Always puts tq to the wheel with the most traction. Transparent operation. Plug and play....+ zero maintenance.


http://www.vmpperformance.com/Eaton-33-Spline-TrueTrac-Differential-for-05-14-8-p/dts-913a701.htm Uses 33 spline axles, like from Strange or Moser. 4 x pinions per side = HD version. But it requires 33 spline axles.

Don't mess rebuilding the oem clutch packs with the rebuild kit. The oem LSD is junk. You will just end up having to rebuild it again and again. It runs way too hot as is. I'd suggest also installing a rear axle catch can, like from bob's autosports. http://shop.bobsautosports.com/Mustang-2005-14-axle-reservoir-KR-style-axle-reservoir.htm Otherwise, you will end up with gear oil all over the road...and there is not much in there to begin with. Gear oil lubes both the differential + both axles.

Dino oil used in either version of the tru-trac. NO synthetic..and NO friction modifier.

 

[Sky Render]

I'm assuming you're doing drag racing.

However, if you're into corner carving, the stock TrackLok will immediately begin to wear out its clutches when cornering with sticky tires.

 

[ChuckyRick]

So general consensus seems to be that a TruTrac would a worthwhile investment, While the axles should be fine for a street/strip car on DR's. Thanks Guys

Anyone bother doing any upgrades with the main cap studs? I noticed Strange actually makes a full replacement billet man cap, So i assume it is a weak point (Eventually). Is this only something to worry about in a drag car cutting low low 60's or would it be $30 cheap insurance/"One less thing to worry about"? Oh one more thing i was going to ask about.. Crush Sleeve Elim kits- Same question as above, Good insurance or unnecessary? Perhaps both would be good ideas just in case i do run a full slick in the future, and at that point about my only weak(ish) link would be stock axles?

Pentalab - Some good info there thanks. I heard tell of our rears puking fluid in standing mile but not on the street. I'll look into a catch can.

 

[pass1over]

crush sleeve elim kits are really just so if you have to take it apart again you don't have to worry about the pinion bearing and the crush sleeve. Just crank it down until it's tight.

 

[ChuckyRick]

crush sleeve elim kits are really just so if you have to take it apart again you don't have to worry about the pinion bearing and the crush sleeve. Just crank it down until it's tight.

Yea that's true. I thought i read a thread before with someone explaining how they launched so hard that it actually crushed the crush sleeve slightly and by the time they got down the track and back to the pits their rear end was almost toast. I can't seem to find it atm, But i swear i read that somewhere lol.

EDIT: So i wasn't completely crazy, Just remembered the effects being more significant than they are
http://www.s197forum.com/forum/showthread.php?t=114334&highlight=crush+sleeve&page=1

 

[RED09GT]

The spider gears are usually the first catastrophic failure point. I lost mine with a dead hook on drag radials at the track. Stock motor/turbo/2 step at 4500 rpm

I put in a Yukon Grizzly locker, it is tough as nails but is kind of a pain in the ass as the ratcheting is noisy and it jumps around when trying to pull the car into a parking spot. Leaves 2 perfect black streaks every time though.

 

[BruceH]

The eaton tru-trac comes in 2 x versions.




Don't mess rebuilding the oem clutch packs with the rebuild kit. The oem LSD is junk.

What's your definition of junk? I made well over 50 passes on the stock LSD without issue. Changed it out for a true track and it appeared to be in pretty good shape. It was one of those deals where I had crushed the crush sleeve during a launch and the rear end had to come apart anyway so why not put a solid sleeve in along with a trutrac?

Anyway I was just wondering when yours failed, most of the people I've known with them don't have issues but it is known that the clutch packs will need to be changed at some point, they are a wear item like any clutch.

 

[Speedboosted]

I'm assuming you're doing drag racing.

However, if you're into corner carving, the stock TrackLok will immediately begin to wear out its clutches when cornering with sticky tires.

I can attest to this. Lots of side to side play in my axles now after just one season of track events. Boss Torsen going in this winter to replace it.

 

[07 Boss]

So general consensus seems to be that a TruTrac would a worthwhile investment, While the axles should be fine for a street/strip car on DR's. Thanks Guys

Anyone bother doing any upgrades with the main cap studs? I noticed Strange actually makes a full replacement billet man cap, So i assume it is a weak point (Eventually). Is this only something to worry about in a drag car cutting low low 60's or would it be $30 cheap insurance/"One less thing to worry about"? Oh one more thing i was going to ask about.. Crush Sleeve Elim kits- Same question as above, Good insurance or unnecessary? Perhaps both would be good ideas just in case i do run a full slick in the future, and at that point about my only weak(ish) link would be stock axles?

Pentalab - Some good info there thanks. I heard tell of our rears puking fluid in standing mile but not on the street. I'll look into a catch can.

I'm a dissenter.

Even though a tru-trac is been shown to hold up pretty good to the abuses of drag racing, helical gear differential are inherently not designed for it. The success it has had at the strip is a testament to it's stoutness, not it's design. Anyways, a good LSD like a Posi or DuraGrip will do just fine and maybe be a bit more reliable. I actually use an Auburn Pro series LSD paired with a set of Richmond 4.10's, but I don't recommend these to a lot of folks for the fact that the way the conical clutches are set up it is not a rebuild-able unit. It is probably the least cost effective LSD unit one could buy. I just think it's a better unit.

 

[Pentalab]

Pentalab - Some good info there thanks. I heard tell of our rears puking fluid in standing mile but not on the street. I'll look into a catch can.

It will puke out fluid at the local strip, ask anyone on here. I was losing some fluid...in just street use.

What's your definition of junk? I made well over 50 passes on the stock LSD without issue. Changed it out for a true track and it appeared to be in pretty good shape. It was one of those deals where I had crushed the crush sleeve during a launch and the rear end had to come apart anyway so why not put a solid sleeve in along with a trutrac?

Anyway I was just wondering when yours failed, most of the people I've known with them don't have issues but it is known that the clutch packs will need to be changed at some point, they are a wear item like any clutch.

50 x 11 sec passes = 9 mins. Add some cornering to the mix, and it all changes...for the worse. If you are paying somebody to do the work, replacing clutch packs is not economical. You will just get a repeat...eventual failure.

I had the tru-trac + WL watts link installed the same day...then never looked back.

 

[bunits19714]

OP- I am assuming your a manual trans? the factory diff if rebuilt correctly with the carbon clutches will hold good enough for your hp level, the axles are the weaker link when combined with the shock of a clutch dump- and dr wheel hoping 40 feet out can wreck havoc on stock axles- it sounds like your going to have limited strip use so I would just rebuild what you have with quality parts and rock it.

 

[ChewyR]

So I make 465 to the wheels. I have bent/warped the stock trak lok 2 times, and broken the spider gears twice in a Yukon dura-trac. I don't have personal experience with the torsen diff, but if it's working for others then hard to argue. I thought about going to a locker, but after reading how bad they are for a driver with a manual tranny I am just going to wait until it breaks again.

 

[Sky Render]

The Torsen is made for road racing and autox. It won't hold up to drag racing.

 

[Marble]

If you stay with the stock Ford piece, even with the carbon fiber clutch pack, you will replace it again. Get the gear driven LSD by eaten and don't worry about it.

I've been there and done that. Learn from others.

 

[Pentalab]

The Torsen is made for road racing and autox. It won't hold up to drag racing.

This. Several pix of the Torsen, blown apart, from drag racing have been posted to S-197 and other forums. The eaton tru-trac is 1/2 the price, and holds up..and also has a 3.5:1 bias ratio.