I posted this on Rennlist and haven't gotten anywhere. I figured I'd see if anyone here on 6speed might know the answer.

I'm getting ready to change the gearbox fluid in my '06 C4S and the owner's manual calls for changing the fluid in my front differential at the same time. There is quite a bit of DIY info out there on changing the gearbox fluid, but extremely little on the front diffy.

For some reason the dealership wants $325.00 to do the fluid change in the front diffy which is almost $70 more than the gearbox (both jobs book at 1.5 hours and call for the same type of fluid). I asked the service manager why the difference and he said it was because of the different fluid amounts between the two. Not sure where these guys learned math . . . the gearbox contains around 3 times as much fluid as the front differential. Something doesn't add up so I am going to tackle the job myself.

Below are photos of a 997 front differential which was removed from a car. If you look at the bottom, you will see two plugs that resemble DRAIN plugs. However only one can be the correct one (I'm guessing #1, but figured I'd ask the forums first). Can anyone confirm? If I am correct and #1 is the drain plug, anyone know what the #2 plug is for? Is #2 a drain plug as well?

Also, based on the drawings in the PET, I am guessing the FILL plug is the one the arrow is pointing to in the second picture. Can anyone confirm that as well? Anyone have any gotchas to share on changing the front diffy fluid? There really isn't much on this subject out there, so any information we can post should be able to help others. Much appreciated.


Sean

 

Sean,

Try posting your question here. https://www.6speedonline.com/forums/...ion-forum-184/

 

Hope these are of some use ... tightening torques are 21 ft-lbs for each.

 

Thanks for the drawings. I'm pretty sure "A" is the fill plug, but is "B" really the drain plug? Drain plugs are usually at the bottom of the sump, and if I opened up "B," it looks like I wouldn't be able to get all the fluid out as the plug in the photo appears to be on the side of the case.


Also, are these drawings for a 997.1 C4 and C4S front differential? The reason I ask is I hear the 997.1 Turbos have 2 drain plugs while the C4 and C4s only have one.


Sean

 

Sorry for the late reply. These are for 997.2 C4/C4S. PM me and I can send you some extra pages with the text if you wish.

A is fill & check plug and B is drain plug.