I have called a couple shops regarding putting a LSD in and they all have told me there is some machining of the falnges

[Kone Killer]

I have a 1999 996, I have called a couple shops regarding putting a LSD in and they all have told me there is some machining of the falnges to properly fit the GT or a OS GIKEN unit. Your thoughts.

V/r

Bob Hallett

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Porsche Tech Article - Replacing Porsche 911 Carrera Limited Slip Differential Carrier Bearings and Seals - Porsche 996 Carrera (1998-2005), Porsche 997 Carrera (2005-2008)

[Nick at Pelican Parts]

The factory 996 LSD obviously fits no problem. As far as a retrofit or aftermarket, you'll have to trust your installer. it depends on the model of the LSD.

I opened a post in our forums, a community member may be able to better answer your question.

- Nick

[BYprodriver]

To install a LSD in the 6-speed transaxle you must shorten & drill a hole in the trans end of both stub axles or use 993 turbo stub axles which bolt on.

[Matt Monson]

Nick,
The factory LSD uses a by in flange, like every LSD that Porsche has ever produced. The reason the aftermarket doesn't make an LSD that attaches with a circlip like the original open differential is because the 996 uses the same differential as a G50 or GT3. The 996 market is no big enough to warrant designing a completely new product line when bolt in flanges are so readily available in the used market or can still be purchased new. Any 993 or 996 GT3 flange can be used as the bolt pattern on the cv hasn't changed.

One can also shorten and through drill the stock flange but shouldn't assume that it is a cheap or easy modification. Those flanges are hardened and don't cut like butter. There is some machine time involved and you must be sure not to over shorten it. If it bottoms out on the body of the LSD that is a bad thing. It needs to bottom on the inner gear to which it bolts, on not on the outer bearing flange.