Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical Chat

Post Reply
 
LinkBack Thread Tools Display Modes
Old 09-07-2016, 05:09 PM   #1
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
Name that Leak - Please?

I've been struggling with fluid leaking from my car since not long after I got it back from the shop.

The patient is a 2004 S 6-Speed

Transmission was rebuilt by G Box less than 5000 miles ago
IMS, RMS, Flywheel and Clutch replaced by a very reputable shop 500 miles ago

200 miles ago I started noticing drips on my garage floor. Cleaned her up real good and it became clear that the leak was coming from the bell housing.

Joe Gibbs DT 40 and the Porsche transmission fluid smell a lot like each other and have the same yellowish color when new - compared them bottle to bottle.

So I got myself a 4 post lift and a transmission stand. Pulled the tranny and here's what I found:


Name:  tranny_3.jpg
Views: 532
Size:  472.1 KB

Fluid pooling in the bell housing

Name:  tranny_2.jpg
Views: 483
Size:  452.6 KB

Behind the flywheel appears to be dry.

Is there an obvious diagnosis or should I proceed to pulling the clutch and the flywheel? What say you experts who are smarter than I? Thanks for the help!


Last edited by hoyabob2003; 09-07-2016 at 05:14 PM.
hoyabob2003 is offline   Reply With Quote
Old 09-07-2016, 07:30 PM   #2
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
...and on further inspection, the inside of the bell housing is coated with an oily substance....if that helps. Thanks!
hoyabob2003 is offline   Reply With Quote
Old 09-07-2016, 08:19 PM   #3
Registered User
 
BYprodriver's Avatar
 
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
Garage
I wonder if the throwout bearing guide collar inner seal was replaced? I would think G-Box would have done that. Have you talked to them ?
__________________
OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
BYprodriver is offline   Reply With Quote
Old 09-07-2016, 08:37 PM   #4
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
Just pulled the tranny today. I'll look at my receipt from gbox. Thanks!
hoyabob2003 is offline   Reply With Quote
Old 09-07-2016, 09:11 PM   #5
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
just checked my gbox receipt. There are actually 2,500 miles on this rebuild that included the os-Giken lsd. The following seals were replaced: main shaft seal, differential side seal and shift arm seal.
hoyabob2003 is offline   Reply With Quote
Old 09-08-2016, 09:19 AM   #6
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
Just spoke to GBox. They were very helpful. I was told that replacing the input shaft seal is pretty straightforward - pick the old one out - tap the new one in - just not too far or it will fall into the transmission. Does this sound about right to everyone? Any pointers?
hoyabob2003 is offline   Reply With Quote
Old 09-08-2016, 01:14 PM   #7
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
GBox needs to give you the tech advice on this, not us !
For example, you need to examine the input shaft for wear/marking where the lip of the seal fits.If there is any discernible marking ,discuss with GBox because fitting a new seal may be futile.
If the marking is slight, can it be 'improved' ?
If it can, is it possible to fit the new seal to a slightly different depth ? GBox to advise.
Similar issues arise with the RMS and sometimes experts(not me) suggest setting the new seal to a different depth to avoid repeat leak problems.
Let us know what happens?
Gelbster is offline   Reply With Quote
Old 09-08-2016, 01:55 PM   #8
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
You're right, I'll be in touch with them again. The guy on the phone did not seem concerned at all. He just told me to get a new seal, pick the old seal out with some picks and tap the new one back in. There is a lip where it is supposed to stop and if you tap the new seal past the lip, it falls into the tranny. You're right though - why did it fail in the first place, only 2500 miles since the rebuild? This can't be a very common problem since I have rarely found this issue mentioned in the forums.
hoyabob2003 is offline   Reply With Quote
Old 09-09-2016, 08:32 PM   #9
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
Well, it was definitely the input shaft seal leaking. Gbox was equally puzzled by this but helpful and responsive over the phone.

They requested that I confirm it was for sure not crankcase oil and that my pilot bearing was not seized or missing.

I pulled the clutch and flywheel - both nearly brand new and in good working order. The RMS and IMS were both dry. I did install a new pilot bearing just to eliminate that as a possibility.

I pulled the main shaft seal of the transmission to find that it was definitely leaking. Interestingly, it was not an OEM part. Comparing the 2 seals side by side, the OEM Porsche part was clearly more robust and had more surface sealing area. I would have expected that a high end company like GBox would have used OEM seals, and perhaps seal failure is really the root cause here.

Then again, only time will tell...

Here's a picture of the 2 seals side by side (The non-OEM seal is damaged due to removal)



hoyabob2003 is offline   Reply With Quote
Old 09-10-2016, 08:33 AM   #10
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
GBox seal fails 6 speed Boxster

Were you just unlucky and got the wrong sub-spec generic seal ? A one-off problem -lets hope.
Or are all the recent GBox 6 speed transmission rebuilds going to fail because of this seal ?
Can you Post the exact markings from the correct seal so we know what to check for?
If you can also give me the markings from the failed seal ,I can research and try to give a comparison of the two specifications.
Gelbster is offline   Reply With Quote
Old 09-10-2016, 09:04 AM   #11
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
The seal is marked 111801 28 40 8R 8 SOG

It looks exactly like this one:

2004 Porsche Boxster S Convertible - Transmission - Page 2

The OEM Porsche Part that I got from the dealer is:

996 301 805 00

There is quite the difference in cost between these 2 - the OEM is 3x the cost - but the photos don't do it justice as the OEM is clearly just a much more robust part.
hoyabob2003 is offline   Reply With Quote
Old 09-10-2016, 09:23 AM   #12
Registered User
 
911monty's Avatar
 
Join Date: Oct 2014
Location: California Central Coast
Posts: 1,476
Garage
Quote:
Originally Posted by hoyabob2003 View Post

There is quite the difference in cost between these 2 - the OEM is 3x the cost - but the photos don't do it justice as the OEM is clearly just a much more robust part.
This is the same thing I found when I changed the output shaft seals on my trans. I ordered the OEM part from Pelican, but when I pulled the existing seal it was clearly a much better part. I then ordered the Porsche seals from Pelican. More money but a much better part.
911monty is offline   Reply With Quote
Old 09-10-2016, 09:30 AM   #13
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
Better seal for 6 speed Getrag input shaft

Looks like that us just a generic seal ;
Also fitted to Mitsubishi. I found generics for $3.This one is branded for $9
MITSUBISHI ENGINE OIL SEAL 28*40*8 R mm NJ 373
Here are some SKF with higher temperature material:
https://www.motionindustries.com/productCatalogSearch.jsp?q=28+X+40+X+10++++MM+A-NBR+SEAL
My personal rules with seals and bearings is to buy the best/most expensive:
https://www.motionindustries.com/productDetail.jsp?sku=00611488
Because the R&R costs 100X that of the generic seal price.
ASk California MotorSports,GTGears, or "Erick"to comment.They are much smarter than me on this issue.
Gelbster is offline   Reply With Quote
Old 09-10-2016, 09:38 AM   #14
Registered User
 
Join Date: May 2016
Location: Minneapolis
Posts: 35
Admittedly, I'm a bit disappointed with GBox for using an inferior part in my rebuild. There's no excuse for having to pull a leaking tranny after 2500 miles.
hoyabob2003 is offline   Reply With Quote
Old 09-10-2016, 09:53 AM   #15
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
Hey it could have been worse:
1. the oil loss could have ruined the new (?) bearings that GBox fitted,
2. the leaking oil could have saturated and ruined the clutch friction plate,
3. you may have confused it with leaking RMS or IMS and replaced them needlessly
4. you may have had to pay an Indie to R&R the box and ship it back to GBox.
This could have been a hugely expensive mistake for both you and GBox. Fortunately ,you did all the work to diagnose and fix the problem and all the R&R .I hope they express their gratitude to you in an appropriate manner. To be fair, the seal may be adequate spec.It may have been a defective seal, seal damaged during installation, gearbox overheated during use/abuse........
I wonder if GBox will contact other customers/Forum members with the same seal to alert them?
Gelbster is offline   Reply With Quote
Old 09-11-2016, 02:13 AM   #16
Registered User
 
Join Date: Jun 2014
Location: LB, Germany
Posts: 1,453
Hello,

the OEM seal has these fine grooves. The after market one on the photos not. Besides material quality this difference in design makes a big difference in how good it can seal.

Regards, Markus


Last edited by Smallblock454; 09-11-2016 at 08:18 AM.
Smallblock454 is offline   Reply With Quote
Post Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 09:15 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page