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GT4 G81 Transmission Failure

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Old 06-11-2018, 01:50 PM
  #1051  
mooty
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Originally Posted by Jnosol View Post
You bought a tranny? That's nuts.
Sorry if I missed it, did you post a DIY on the 3rd gear replacement?
i can't DIY
i bought a new box, dealer put it in
i took the bad box send to gearbox buy, disassembled for forensics
this was a year ago.
that's how i knew the failure was not driver error.
as originally i thought i blew it.
then soon after my box, i hear more more and more of the same issue same symptom.
and i know several cars where the replacement failed for the same issue.
i gave up on the car, i was first adoptor of the platform, 2006 first cay S in CA. that had issues too.
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Old 06-12-2018, 09:37 AM
  #1052  
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Originally Posted by Jnosol View Post
Was anyone able to convince your dealer to replace the 3rd gear with Holinger instead of just replacing the whole tranny when 3rd gear fails? I would doubt they would.

Below are the photos of the Porsche weak welded 3rd gear vs Holinger. (OEM photos from Sharkwerk Mule car vs Holinger 3rd gear)
Unless Porsche made that gear weak to prevent catastrophic failure to other drivetrain parts under high stress?


I sure hope that Holinger gear stays together. They haven't even bothered to peen the dog after they put it on. This is the right way to do it. They may be creating a whole new round of failures with their shoddy workmanship. One of many reasons we fired them a dozen years ago.

And no, Porsche didn't make them weak on purpose. In all likelihood Porsche didn't even know that Getrag changed from splined to welded. I'll never understand the decision unless it was based on a couple bucks cost. All 987 gearboxes have splined 3rd and 4th gears and welded 5th and 6th gears. It makes sense because on the lower gears the dog overhangs the body of the gear. It can flex. This is, I believe, the root cause of the failure (and the same reason the Holinger dogs might walk right off the gears). I doubt the change had anything to do with reliability and everything to do with manufacturing cost. Doing all those parts smooth and just welding them together is far less expensive than cutting splines on both the gears and the dogs.
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Old 06-12-2018, 03:09 PM
  #1053  
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Originally Posted by GTgears View Post
I sure hope that Holinger gear stays together. They haven't even bothered to peen the dog after they put it on. This is the right way to do it. They may be creating a whole new round of failures with their shoddy workmanship. One of many reasons we fired them a dozen years ago.

And no, Porsche didn't make them weak on purpose. In all likelihood Porsche didn't even know that Getrag changed from splined to welded. I'll never understand the decision unless it was based on a couple bucks cost. All 987 gearboxes have splined 3rd and 4th gears and welded 5th and 6th gears. It makes sense because on the lower gears the dog overhangs the body of the gear. It can flex. This is, I believe, the root cause of the failure (and the same reason the Holinger dogs might walk right off the gears). I doubt the change had anything to do with reliability and everything to do with manufacturing cost. Doing all those parts smooth and just welding them together is far less expensive than cutting splines on both the gears and the dogs.
Good info. Which brand is best for replacement gear?
My new tranny is on order. I was told that Porsche has revised the 3rd gear for the replacement tranny. But if it fails again, I'll have to force the dealer to replace the 3rd gear with after market ones due to safety concerns.
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Old 06-12-2018, 11:53 PM
  #1054  
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I figured I’d add myself to the list of latest 3rd gear failures. 19,700 road miles and a week before it’s scheduled service. Car completed April “16, and third failed after a downshift from fourth to overtake on the highway at about 60 mph and gaining momentum. Should be finished up tomorrow, brought it in last Tuesday, so 8 days or so with a dealer provided rental. Looking forward to a smooth as soft butter new tranny.
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Old 06-13-2018, 10:20 AM
  #1055  
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Originally Posted by Jnosol View Post
Good info. Which brand is best for replacement gear?
Is this a trick question?
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Old 06-13-2018, 03:07 PM
  #1056  
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^ lmao
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Old 06-13-2018, 03:13 PM
  #1057  
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Lol, come on Jimmy!

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Old 06-13-2018, 03:17 PM
  #1058  
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Originally Posted by GTgears View Post

... I'll never understand the decision unless it was based on a couple bucks cost.
You actually do understand, one just doesn't really want to believe it.
Almost every major issue (since 996, 986, M9x, 9A1) relates to saving a few bucks on parts.
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Old 06-14-2018, 10:28 AM
  #1059  
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Originally Posted by GTgears View Post
Is this a trick question?
Bahahah. I didn't even read the screen name.
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