bigds01

So the front diff on my 29k 2009 6mt failed. The car would lock up in reverse. It failed while I was driving slow on approach to the George Washington Bridge in New York.

No clue as the car has never been raced why it would have failed. Has anyone else had their's fail without a fluid leak? Any root cause analysis performed?

Dennis C

I had this problem on my 996 C4S, although it began to leak before failure. I never had any issue with the 997 TT.

If they approach the 997 repair the same way as the 996 repair, then the dealer will tell you that the entire front differential needs to be replaced. As I recall, the part alone is over $7K. My independent mechanic was able to rebuild my front differential for about half that cost. Hopefully you'll find a good solution for the 997 TT.

Good luck!

bigds01

I am just replacing the unit. It isn't a repairable unit. I sourced a very reasonably priced one.

Dennis C

They said that the differential for the 996 wasn't a repairable unit either. It was repairable.

Glad you found one for a reasonable price!

Are you running wheel or tire sizes that are considerably different from OE sizes? Just curious.

bigds01

Stock wheels with sottozerro's for the winter. They drained the old diff today and metal chunks came out

Dennis C

Interesting... surprising that it failed like that.

bigds01

I have owned the car for 5k miles and it hasn't been hooned. I know the previous owner didn't either. Just weird. It was near the end of a 400 mile trip that day

CodeRed

I would seriously consider deleting it altogether at a $7k cost to replace it

bigds01

Except the whole reason I got it was to drive in the winter

TT Surgeon

One thing known to fry the front diff is out of spec tire sizes fr to rear. If your snow tires are more than 4% off that might be the issue.

bigds01

295's on the rears

TT Surgeon

It's diameter of the front to rear ratio what's important, I bet you have a greater than 5% differential fr to rr vs stock.

bigds01

The front's are 235/35/19 and the rears 295/35/19 Sottozerro II's . Would that cause an issue?

fresh-popcorn

Aren't the rears suppose to be 295/30/19 and not 35?

Harry Da Hamster

Weird you had this issue. I'm thinking some sort of neglect from the previous owner. Perhaps he had a spare of some sort on a front wheel? Or ran one of the two tires pretty low and continued to drive? Or maybe you're just the statistic...?