996/997 GT3 Diff Rebuild: Anyone Done it?

[GentlePersuasion]

Hi Folks,

It seems fairly clear now that the diff plates on these cars are made from chocolate; finest 70% coco variety I'm sure, but chocolate all the same. The method to test for a worn out diff appears to be inconclusive, but despite this, I am concerned that there's little or no assistance from my diff when coming out of light speed. I'm still getting lockup out of the corners, but the diff is far from aggressive in any way and the car is very nervous under hard braking (despite a recent geo set-up at JAZ).

Conclusion: the diff's fked.

Now, where do I get it sorted (I'm London based)? Anyone got experience of this? The car's still under warranty (although my friendly OPC has since drawn a blank on any notion of an FoC rebuild), so on that basis, I'd rather have the standard LSD rebuilt with stronger internals than do anything too drastic.

I've heard that the 'Cup' internals are the way to go? Thoughts?

[jeremyc]

Just had mine done.

Take a short trip down the M23 to see Nine Excellence; get them to replace with Cup diff plates.

Job's a goodun'.

[thegoose]

If it's under Porsche warranty then its down to them to sort it out - but it'd be nice if you could just pay the cost different to change to the Motorsport part. I believe the part cost is similar but it requires a little more time & skill to set up correctly - but it is indeed much better quality.

[sleep envy]

Take it back to Steve at Jaz and asking him very kindly to put the cup plates in.

Just don't drink the tea.

[sleep envy]

thegoose said:

If it's under Porsche warranty then its down to them to sort it out.

To replace a consumable part?

[GentlePersuasion]

sleep envy said:

thegoose said:

If it's under Porsche warranty then its down to them to sort it out.

To replace a consumable part?

Indeed. It was worth asking, but alas, the diff packs are covered under the same umbrella as brakes and clutches; i.e. "Go forth and multiply. Sir".

Edited by GentlePersuasion on Tuesday 12th February 12:23

[fioran0]

Pretty much everyone with a non garage queen milaged GT3 should have had diff rebuilds. It's nothing to be concerned about. As you are aware, the street plates aren't very robust and track driving will finish them off in short order. Just use some of the Cup discs instead of the regular street ones when you rebuild. Fwiw the Cup also uses more discs in its diff stack so mostly you don't want it rebuilt actually to Cup spec or else you may wrestle with the diff on the street.
There is an actual test you can do to check, Porsche give the exact values for brakeaway torque so its not anything mystical that's involved to confirm. .
Instability under braking is the first sign of one being worn from the drivers seat however.

Mike at Sports and Classic would get the usual nod but he may be too far up North for you.

[ontheloop]

JZM rebuilt the diff on my 996.2 GT3 with cup plates last summer and I was very happy with the results.