Did a drain, flush, fill of the rear diff and cooler. Turns out there was a bit of grime in there!

Found the fill and drain plug and filter housing. I did need to loosen up the rear exhaust heat shield so the filter would have enough room to pull out completely.



Drained and removed the filter. There was a LOT of black and ferrous grime in the oil and filter, took a picture of what was sticking in the pan as I emptied it.





Decided to replace the filter as there was a cheaper OEM alternative available, given the unit is made by Graziano, the filter is used in other applications:



See the difference? me neither. Lambo part #0B9525558 on right. (also available as Ferrari 143939 )

I then refilled with cheap EP gear oil to flush out system.


Ran the car while lifted to run the oil through the diff casing and the cooler core. Caution! Turn off DSC completely. And you'll get ABS errors that you'll need to reset.



Then drained oil, removed cooler core and drained it as well. Got a lot of grime out again, especially in the core. I drained dripped the core through a metallic nut holder bowl and you can clearly see the ferrous material sticking to the magnet outlines.



Used a high pressure cooler cleaning product and flushed the core out with it, got a lot of grime, ferrous material and even bits of aluminum out.






Afterwards, ran compressed air through the cooler to flush out the cleaning solution and dry it out.

Finally, changed the drain plug out with one with a stronger and larger neodymium magnet. It's a standard drain plug size M18x1.5, so I got one spec'd for a Porsche with copper washer. I filled up the cooler core with oil and used temporary plugs so I could re-install without spilling it.
Will need 2x Oetiker 18.5mm replacement clamps to reinstall the cooler.







As for lubricant, after a lot of research , I went high end with HPL 75w90 Limited Slip oil. Feel free to consult BobIsTheOilGuy for any independent info on HPL as a boutique blender.


Refilled, the pumpkin, reinstalled the cooler, ran the car again and re-checked the level. One thing that's immediately obvious from the lack of smell is that it's not a traditional Sulfur Phosphorus based gear oil so it's a lot kinder to yellow metals.

All Good!

 

Most likely the wear comes from the LSD clutch/friction plates.
How many km/miles on the unit?

Are you sure about the oil?
Just asking, because AFAIK both gearbox and LSD share the oil if you have a transaxle unit.

 

25k km.

The transaxle does not share fluid with the final drive. I'm quite sure of the oil spec of the final drive unit.

Each has their own fluid, the ZF 8HP fluid has much different ATF like properties. I'm doing that one next.

 

OK, then the oil is fine.

 

Nice write up …and a job done well….thanks eh..

 

Very thorough how to with great pictures. The one thing I could add is the LSD clutches need the fresh fluid to circulate thru the pack. So I would recommend driving in figure 8's or circles in a open area to allow the clean fluid to cycle through if one has any type of chatter problem.
Thanks again for your detailed how to.
-JW

 

Very nice write-up, thanks!
Did the gasket come with the filter, or you got it separately?

 

Thanks! Had to buy the O-Ring separately,
It's "Metric Buna O-rings 20.63 x 2.62mm"

They're cheap and I had to buy 10! Which still came in cheaper than Aston's part $ for the same oring. Let me know if you need a couple I can throw some in a regular envelope and send your way if you need any.

 

Thanks for these detailed write-ups. I appreciate it!