Notices
Boxster & Boxster S (986) Forum
Sponsored by:
Sponsored by:

2.5 plug on manual transmission?

 
Old 05-30-2019, 07:28 AM
  #1  
John McM
Addict
Rennlist Member
Thread Starter
 
John McM's Avatar
 
Join Date: May 2001
Location: Auckland, New Zealand.
Posts: 11,943
Received 10 Likes on 9 Posts
Default 2.5 plug on manual transmission?

Just doing my first transmission oil change on my new to me '99 2.5 manual.

First question. I mistakenly thought this torx headed bolt was the fill plug. I now know it's not. However what is this plug for?

Second question. I see a few posts about a special oil for the 2.5 5 speed. Bentley just has Hypojd gear oil SAE 75w90 in its description. What is the special oil?
Attached Images   
John McM is offline  
Old 05-30-2019, 03:35 PM
  #2  
Quadcammer
Super User
 
Join Date: Nov 2006
Location: Clifton, NJ
Posts: 12,820
Likes: 0
Received 9 Likes on 7 Posts
Default

I believe thats a shift fork/selector shaft retaining bolt.

I've used both Mobil Delvac 75w-90 and the Porsche OE gear oil with similar results
Quadcammer is offline  
Old 05-30-2019, 04:00 PM
  #3  
John McM
Addict
Rennlist Member
Thread Starter
 
John McM's Avatar
 
Join Date: May 2001
Location: Auckland, New Zealand.
Posts: 11,943
Received 10 Likes on 9 Posts
Default

Originally Posted by Quadcammer
I believe thats a shift fork/selector shaft retaining bolt.

I've used both Mobil Delvac 75w-90 and the Porsche OE gear oil with similar results
Thanks for the response. The various books and DIY threads don't cover that detail. I became suspicious when I realised I was looking for a 17mm Hex bolt, which this wasn't and it looked impossible to fill the transmission through this one Hopefully no harm done as it has no room to adjust anything and I haven't selected gears etc.
John McM is offline  
Old 05-31-2019, 07:50 AM
  #4  
John McM
Addict
Rennlist Member
Thread Starter
 
John McM's Avatar
 
Join Date: May 2001
Location: Auckland, New Zealand.
Posts: 11,943
Received 10 Likes on 9 Posts
Default

I refitted that bolt, found the correct fill bolt/plug (driver side on LHD cars) and put 2.25 litres of 75w/90 gear oil in. I used a bent paper clip to measure the oil level. All good.
Attached Images   
John McM is offline  
Old 06-01-2019, 02:45 PM
  #5  
KevinGross
Addict
Rennlist Member
 
KevinGross's Avatar
 
Join Date: Dec 2004
Location: Stow, MA, USA
Posts: 1,020
Likes: 0
Received 4 Likes on 3 Posts
Default

Well done. Porsche did originally spec an unusual oil for the five-speed G86, but has since superseded that recommendation to the same 75W90 that they recommend for most if not all transmissions. Your five-speed has the same VW 012 series synchros as used in the 968 and a bunch of Audi gearboxes, so nothing particularly special in that department that would motivate something different.

I assume you were able to remove the 16 mm XZN tamper-proof drain plug without difficulty. It can be replaced with the same 24 mm taper plug, not tamper proof, as used in the fill bore to simplify life in the future. Cheers,
KevinGross is offline  
Old 06-01-2019, 03:55 PM
  #6  
John McM
Addict
Rennlist Member
Thread Starter
 
John McM's Avatar
 
Join Date: May 2001
Location: Auckland, New Zealand.
Posts: 11,943
Received 10 Likes on 9 Posts
Default

I bought the special tool so didn't feel ready to make that redundant the drain plug didn't give me any issues although I sweated with the fill plug as I had drained the oil first after undoing the wrong one. It was on a lot tighter than spec. Not much in the oil so it must have been done sometime in the last 20 years.

The test drive was uneventful. It's a really nice shifting box. Next up is the power steering pump pulley. That area was very hot at my last track day.
Attached Images   
John McM is offline  
Old 06-27-2019, 03:12 AM
  #7  
ard
User
 
ard's Avatar
 
Join Date: Sep 2004
Location: NorCal
Posts: 389
Likes: 0
Received 1 Like on 1 Post
Default

I usually wrap one end of the paperclip around a washer with a larger diameter than the fill plug hole just in case it slips out of my hand it won't be able to fall into the gearbox.
ard is offline  
Old 06-27-2019, 08:40 AM
  #8  
Starter986
User
 
Join Date: Sep 2018
Posts: 62
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by ard View Post
I usually wrap one end of the paperclip around a washer with a larger diameter than the fill plug hole just in case it slips out of my hand it won't be able to fall into the gearbox.

Brilliant.
Starter986 is offline  

Thread Tools
Search this Thread

Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: