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996 Turbo Gearbox/differential oil leak

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Old 12-01-2017, 03:57 AM
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mat59
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Default 996 Turbo Gearbox/differential oil leak

Anyone know what’s going on here? Have a small leak. Images below. Taken on right side (passengers side).





Thanks!
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Old 12-01-2017, 12:14 PM
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Not the best views but if I had to guess I'd have to say axle flange seals. The ones in my 2003 Turbo's front diff developed leaks at somewhere around 100K miles. Tech replaced then and topped up the diff fluid level -- which fortunately wasn't real low -- and the new seals have been fluid tight ever since. Diff's ok too.
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Old 12-01-2017, 02:53 PM
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garrett376
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Is that CHF, or trans oil? I'd bet your clutch slave is leaking.
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Old 12-01-2017, 05:54 PM
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Looks to me the shift select seal is leaking, need to take the trans off and dismantle to fix it! The upper area where the select lever goes into the trans!
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Old 12-02-2017, 02:31 AM
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Yeah, I have several very similar looking pictures from when I did my slave/accumulator.

Gear oil has a very distinctive smell and quite different from the Pentosin found in the clutch slave circuit. Swipe that drop off the trans and have a whiff. If it makes you go “whoa!”, then its gear oil. If not, Pentosin.

I’d bet it’s Pentosin and either your slave or accumulator is leaking.
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Old 12-02-2017, 04:19 AM
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Originally Posted by garrett376 View Post
Is that CHF, or trans oil? I'd bet your clutch slave is leaking.
Yep, look leak above
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Old 12-02-2017, 01:49 PM
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If you look at the second picture the leak seems to come from higher up and if you look at the picture of the engine on the bench , the slave can be the problem....
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Old 12-02-2017, 02:08 PM
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Best thing to do is clean it all up thoroughly and keep an eye on it, to pinpoint the leak.
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Old 12-07-2017, 01:29 PM
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OP here. It was the rear differential seal in the end.
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Old 12-20-2017, 10:23 AM
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....and it’s not the axle seal after all. Turns out it’s the dreaded gear selector seal. Gearbox has to come out. Not great news. Now researching rebuilds as second gear synchro is weak. Makes sense to get it done whilst box is out.
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Old 12-20-2017, 01:17 PM
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Sorry to hear it, thats what I thought! Good luck! Since it will have to be opened, maybe a second gear synchro replace or inspection, and pinion bearing inspection. Might be a good time!
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Old 12-20-2017, 01:35 PM
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Originally Posted by mat59
....and it’s not the axle seal after all. Turns out it’s the dreaded gear selector seal. Gearbox has to come out. Not great news. Now researching rebuilds as second gear synchro is weak. Makes sense to get it done whilst box is out.
997gt2 1-3 gear all steel syncros 1-6 gt3 shift selector send it to rader transmission cost is under 7k$ if you pull it and ship it. Add a wavetrac while your in there
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Old 12-21-2017, 11:12 PM
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mat59
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Originally Posted by 32krazy! View Post
997gt2 1-3 gear all steel syncros 1-6 gt3 shift selector send it to rader transmission cost is under 7k$ if you pull it and ship it. Add a wavetrac while your in there
Thanks. Will take a look
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