WOW, the 997 LSD inner look really cheaply made compare with 996. That is too bad that Porsche fall into the same trap of cost saving by sacrificing quality. I heard that the new titanium center exhaust found on GT3 R and RS are cheaply made to save cost and it does not hold up to rigor of race and the damn thing has been blowing up. I feel better the fact that my ramps have been replaced with your beefy GT gears

 

Thanks for the kudos. That was in fact your LSD.

 

This is the most imformative thread that I read! I would name it the best technical thread for 2009:-) thanks to Matt and Mikymu.
I just bought a 996 Gt3 and it needed a LSD rebuild! Matt, can you PM with quote? I will ship it to you.

Michael

 

...sent

 

i bet no one has seen LSD damage like this one! 996 GT3



the damage you see is on a REBUILT diff that my porsche stealer performed under warranty with factory OE 996 gt3 parts. this damage occured after 1yr and 1k miles of NON track, STREET only driving.

warranty denied... stealer and PCNA rep said: "customer abuse. possibly hit a patch of black ice. taking corners too hard. or worse, he may have driven the 996 gt3 on a race track! oh the horror!"

so stealer "graciously" offered to rebuild the diff again at a bargin discounted price of $3,000. eh... i said "no thanks" and diff went to matt at guards and matt did it right. i guess i can now go drive on "black ice" and take corners "too hard". stupid stealer

great thread and info here, thanks for letting me vent!

 

Excellent Michael. Matt will take good care of you.

WOW! They really botch the job and looks horrible after only 1K miles of none track use and they want to charge $3K??? Unbelievable. You earn the right to vent buddy!

 

Talked to Matt and he was helpful. I will take the LSD out and ship to Matt. My next track day is May22nd...Can't wait!

 

I'm getting a number of questions about the ring gear, so I thought I would make a post about it. Here's a picture of the LSD with the ring gear still attached:


Here's with the ring gear removed:


I encourage people to remove the ring gear before sending the LSD to me because of the risk of damage more than anything else. A ring and pinion set is almost $3000. They are matched sets and if the ring is damaged in shipping the whole set needs replacement. Furthermore, because it requires resetting the pinion depth, along with ring gear preload and backlash, it's generally $1000 or more in labor to put into the gearbox.

While insurance is a wonderful thing for if UPS messes it up, it usually takes up to 100 days to get paid. And that's if they pay it. They often claim that it was packaged inadequately and dump it back in your lap.

So, if people have the ability to remove and reinstall the ring gear themselves on their end it's a much safer approach than shipping it to me with the ring attached. If you have no other option, I am happy to remove and reinstall it for you. I do add $50 in labor for the extra time and it does increase the shipping charges a bit. I just figured I would put it out there because so many of the DIYers doing this work have been asking me specifically about the ring gear. This puts it up there for all to see and ask questions if it's not clear.

regards,

Matt

 

Matt,

Are there any trick on removing the ring gear from the diff?!

 

It's on there at about 125ft/lbs so air tools are really the way to go for getting it off.

Then you've got to heat it a bit and actually wack it loose of the differential body with a rubber/plastic mallet. It's on there pretty tight and doesn't want to come off too easily.

For reinstallation, we "chock" it in a vise (with aluminum between the vise teeth and diff. body to avoid marring it) and torque them back on in a start pattern like you would a flywheel. I generally bring it up to about 75-85ft/lbs on all bolts and then take it up to 125 from there.

 

Thanks for the info.. !!

Do you use a torch to heat up the ring gear?

 

Yes, we heat the ring gear with a torch. There's a number of interference fits parts in a Porsche gearbox and heat is often used to make removal or installation easier.

On reinstallation, you can generally get it to seat far enough to get the first row of threads started on a few bolts. Then you systematically use the bolts to pull it tight in an equalized and even pattern. Once you've got it pulled on and in place with 3 or 4 bolts you can put the rest in and start torquing them.

 

Very useful information, thanks Matt!

Not that I plan to do this myself anytime soon (if ever!) but I appreciate that you are always willing to share your knowledge!

 

You're welcome. I try. I had a guy call me today and ask some questions about a differential. When we were done he apologized for not buying something. That's just not how I look at it. I know some vendors act like if you aren't spending money you are wasting their time. That's not me. I'm happy to help, and educate, and also to learn.

 

That is great, Matt.. and it is behavior like this that would make me a future customer!

I remember another vendor basically just shut me off when I asked how their product works (I asked for a side by side comparison between their "improved" version and the stock version). I was told that if they show that to me, then what's the point..

My take on that is.. first, you need to convince me that it works by showing me what's the difference and tell me why it makes a difference.. second, even if I know exactly what's the difference.. it is not like I have a CNC machine or mill/lathe at home that I can just make it at home.. LOL! So just from their very defensive response, it completed turned me off on their products.

Anyway, like I said, I appreciate you always taking the time to answer our questions. You are a great asset to the forum.