Transmission gear oil change made easy.

[steved0x]

This article shows some pictures of the fill and drain plugs for our transmissions as well:

Porsche Boxster Differential / Manual Transmission Fluid Change - 986 / 987 (1997-08) - Pelican Parts Technical Article

[Dave80GTSi]

First off, my sincere thanks for everyone who has taken their time to respond on this one. It’s been a bit of a puzzle to me, as you can easily see!

Referencing the 986 Parts Catalog, I have identified the items in question as nos. 10 to 12 in the enclosed picture.

In case the photographed text is not clear:

Item 10 is labeled as “Hexagon-head bolt M8 x 55”
Item 11 is labeled as “Screw plug M22 x 1.5”
Item 12 is labeled as “Sealing ring A22 x 27”.

Based upon this, it seems quite apparent to me that items 11 and 12 are intended to be used as an oil drain and/or fill plug.

It would “seem” at first glance that item no. 10 could perhaps be intended for use as a fill plug, so that’s why I removed it for a look.

And when I removed item no. 10, I can confirm that it was a standard partial thread hex head bolt, a bit more than 2 inches long (their 55 mm length sounds right) with threads over only the final ¾” / 20 mm or thereabouts. It removed very easily, and likewise I was able to reinsert it without any drama or difficulty. No sounds of anything dropping into the tranny, nor indications of cross-threading, nor anything else ominous like that.

Thinking about this further, 8 mm does indeed seem like a very small diameter hole to be primarily used for a fluid fill port.

I would certainly like to believe that, if the casual removal of bolt no. 10 resulted in critical internal bits being dislodged with the potential for catastrophic consequences, they would not have used a standard hex head bolt for this function, but instead perhaps some sort of a fancy tamper-proof bolt so to discourage the casually curious folks like myself.

Thanks - DM

[78F350]

Originally Posted by Dave80GTSi

...Based upon this, it seems quite apparent to me that items 11 and 12 are intended to be used as an oil drain and/or fill plug.

It would “seem” at first glance that item no. 10 could perhaps be intended for use as a fill plug, so that’s why I removed it for a look.

... they would not have used a standard hex head bolt for this function, but instead perhaps some sort of a fancy tamper-proof bolt so to discourage the casually curious folks like myself.

The Drain plug is on the bottom of the differential.
The Fill plug is on the side of the differential

Originally Posted by 911monty

Look at my first post, 3rd picture. You can see the fill plug left of the axle flange. The drain plug is where the plastic jug is, below the axle shafts. You are looking on the gearbox, the drain and fill are on the differential. ...

Fill Plug(Make sure that you can loosen it before you drain the old oil):


Drain Plug:


Those bolts on the side of the transmission that Dave80GTSi is playing with are obviously just shills to discourage people who don't read directions from tampering with the important stuff.

I think that the intent of this thread was to point out that drilling a hole in the pan beneath the drain plug makes servicing the transmission a lot easier. (Thanks Monty)