COMBO:
Heads, Cam & Bolt-Ons
6MN
AMS built rear diff with 3.90:1 gear & LPE Harden Output Shaft, about 4000 miles
DTE Differential Struct, about 4000 miles
Spec Stage 4f Clutch, about 1000 miles
Nitto Drag Radials.

Took it to the track, and the rear diff shreaded on the 1st Launch
Here are the pix:


You can already see the cracks.


The passenger side half shaft won't come off, so we started unbolting the cover while the half shaft was still attached.


Oops, there goes some of the rear diff.




The ring is missing some teeth, and we have lots of metal shavings.


The pinion is also destroyed.

 

Wow, that's a lot of damage to the differential! I just had the DTE strut installed on mine and thought it would have prevented this from happening.
Those Nitto's must have really stuck on your launch. How hard did you come off the line?

 

what was your 60' time .... wow.. usually dont see that much carnage without slicks...

 

Ahh yes, nothing like the smell or read end fluid in the morning.
I strong suggest staying away from the 3.90 gear set. They appear to be the weakest of the bunch.

Phil

 

Do both your shafts look good? You mentioned the pinion support was toast, was it the stocker? Pre load springs? Sorry for the questions, just trying to determine the culprit. Good luck on getting back together asap.

 

Unfortunately I have seen this type of damage on an older vet. My 64. Blew the diff.. just about as bad as yours. NO fun. I could not get the half shafts out either. Had to use 1 flat turn on the wrench for the entire bolt lengths took hours.

Best of luck 99 Nassau Blue

 

Hard to imagine it being much worse without the differential brace. Any damage to the transmission?

 

One final questions, probably not the culprit, but was your brace set correctly to zero lash?

 

all of that DTE stuff and it did that?

drag racing myth 101: DR's are easier on the driveline than et streets or slicks.

If a stiff sidewall DR actually grabs HARD, I think they're harder on the driveline than a krinkling et street or slick. Those DR's simply transfer the anger to the next weakest spot alot more abrupty.

 

The rear diff is not DTE but AMS with LPE harden output shaft as I stated above.
I followed DTE struct installation to the dot, I even called DTE to make sure I was doing it correctly.
I can't offer you the 60', it broke on the 1st launch.
The output shafts seems OK, and the tranny does not appeared to be damaged.

 

Chalk another differential death up for Nitto Drag Radials...

 

damn would mickey thompson or bfg's be just as hard on the diff.

AMS from dallas thats outta biz now? if so i've heard shaddy things about that shop

 

I thought all of that additional bracing on the DTE strut would have kept the casing in one piece.

 

What RPM did you launch at?

Sorry to see the carnage.

 

The DTE Differential Strut was engineered to prevent the differential from fracturing away from the transmission that would otherwise cause the transmission itself to also be damaged beyond repair in this scenario. In this instance, our product performed as designed according the owner's comments.

Furthermore, the majority of the surface area of the differential case that actually had the strut girdleing surrounding it also remained intact,
which was also an engineering feature that performed as designed, even in the face of internal catastrophic differential failure.

When a differential such as this fails internally as bad as this one has, components often shear/fracture/crack off which causes broken pieces to toss around within the internally spinning (or heavily loaded) gear-train. The tolerances in ANY of these differentials are very tight, so when a foriegn object is jammed into the other moving components, a lock-up condition occurs and something MUST give... In this situation, it was the lower portion of the unprotected case.

There are many causes for differential failure in a racing environment and most here know what they are. The differential strut is not designed to strengthen the internal components themselves, but to provide as much rigidity to the case as reasonably possible within the given package from Getrag for which it performed as designed. Internal component failure leading to explosion of the case is not related to the function of the DTE Differential Strut for its engineered purpose.

Given the extent of this type of catastophic internal differential failure, it would certainly suggest that had the DTE Differential Strut NOT been used as it was, the owner would also be replacing his transmission as well....

 

I have seen it many times here. D/R's cause far more damage then ET streets.

 

So could the new ETstreet Radial be a good compromise. Thicker sidewall on the 275/40. I just posted on this comparison looking for thoughts. earlier today

 

So much for the brace!

 

Makes sense. Thanks for the good explanation. Nothing could have stopped that ring and pinion from being ruined. And indeed the case cracked only in the unprotected area. With what happened on the inside something had to give. Nice design.

 

I can't think of anyone making big power that uses a 3:90 gear that hasn't had problems.

How hard were you launching ?????????????????????????????????

As stated earlier, the benefit of the DTE brace is the protection of the trans. It's better to replace a diff than a diff and a trans.

Cheers,

Mark