2004 CTT Differential Question

[clarksongli]

Hi, I've been lurking for a while with my 2004 CTT. I love the car and haven't really had many issues other than the normal coolant pipes.

I do all my own work, and this is my dail driver, so the work is much more simple than my other cars.

I have two, hopefully, basic questions:

1. the Diff "Locks"...are those viscous diffs or truely locking?

2. Because Burmah oil is hard to come by in the states, is there a fluid that is recommended other than the porsche part? i know redline has a gl5 rated fluid, but if there are clutchpacks in the lockers....i would hate to decrease the locking ability of the discs by using a full synthetic oil.

I've seen people using M1, Redline MT-90 all the way to 75w-90 GL5, AMSOIL...

My theory is if the lockers are truely mechanical, then i won't be as worried with a change in gear oil....but if they do rely on friction discs.....i'll stick with the OEM.

TIA

[hahnmgh63]

I used Redline 75w90, I wouldn't recommend the MT-90 as it is only a GL4 and the Burmah is a GL5. I haven't noticed a change since swapping it 5K ago at 60K miles but the OEM fluid front & rear was definitely dirty. I also put Redline D5 ATF in the transfer case (not too bad looking compared to the diff fluid) and will do the tranny fluid this Spring.

[deilenberger]

Ummm.. dunno if you noticed - but there is a pinned thread right at the top of the forum. One guess on the subject..

[working4it]

Check my profile gallery and you will see the difference in old vs. New. The front was very dirty the rear not too bad. I went with Mobil 1 LS 75w90 but like Amsoil and redline

[clarksongli]

Thanks everyone.

I do know there is a pinned thread at the top, but with no real answer to fluids vs. diff properties. The reason i ask about the differential internals is because friction material is much more likely to NOT be compatible than a standard locking differential.

I was hoping someone here....maybe Loren, would know if cayennes utilize traditional mechanical lockers, or if we are using the typical clutch type, which are found in almost all "locking diffs" now.

[wvicary]

Actually I think it has both friction disks and you can mechanically lock the front differential and the rear if you have that option.

[clarksongli]

Actually I think it has both friction disks and you can mechanically lock the front differential and the rear if you have that option.

Yeah i was looking at the parts drawings and it lists the Diff as an LSD or non LSD....so i took that as not "true locking"