A the title suggests, I'm wanting to know what the rebuild interval is for the viscous couplings in our AWD Magnas.

Their arrangement - oil sealed in a container packed full of friction onagers - to me suggests that they do eventually need servicing.

I've asked "the Internet" and the answer in get back is 100,000km. Which, if true, kinda blows.

For bonus points - and this isn't something I'm looking to do - does quaiffe (or another diff' manufacturer) make an LSD to replace the open front diff'?

Interesting topic Skapper, I'm looking forward to the responses.
I also found the 100,000 k figure when I went looking. I guess at that point we will need to regularly monitor them to detect when they fail.
So I'd also like to add another question here; what is the best on-car method for testing the LSD to determine that its still operating correctly?

Interesting topic Skapper, I'm looking forward to the responses. I also found the 100,000 k figure when I went looking. I guess at that point we will need to regularly monitor them to detect when they fail. So I'd also like to add another question here; what is the best on-car method for testing the LSD to determine that its still operating correctly?

According to the manual it's to disconnect the drive shaft and rotate the rear wheels.

I haven't looked for a test procedure for the transfer LSD. Might do that later.

I'm going to add yet ANOTHER question to the list - Center bearings; anybody had to replace theirs? Do we have a part number, either genuine or aftermarket?

According to the manual it's to disconnect the drive shaft and rotate the rear wheels.
You mean to see that they rotate in the same direction? I wonder if that test might be positive on an older LSD while under load it still fails? Or maybe once the fluid has expired this test is enough to prove it? I can imagine all sorts of scenarios...
I was hoping we would be able to run the car onto a purpose built testing machine and somehow test it under load?

Yeah, it's my understanding the wheels should rotate in the same direction once the drive shaft is disconnected. Haven't tried it.

I remember watching a YouTube video of guys driving their AWD cars across a ramp - just one side of the car crossing the ramp. The ramp was made up of rollers which simulated a loss of traction.

http://youtu.be/tpp5tW71qYI

http://youtu.be/tpp5tW71qYI
Wow, now that would have to heat up the VCU's fluid