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Discussion Starter #1 (Edited)
Hi

I´m thinking in changing the gearbox oil of my 75 Turbo.
Since I bought the car, the LSD rarely works, but I know the previous owner repaired the gearbox.
So I suspect the LSD is shot or it has the wrong oil (not for LSD).
Now I will try an oil for LSD, and if it doen´t do anything different than before, I have to renew the LSD.
So the question is, does anyone have experience with Motul 90PA 90?
They say its for LSD diferentials
I dont want to fill with an expensive oil for now because if it doest work is money to the trash can.

Edit: its not 90LA, its 90PA 90
 

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oil for LSD will kill the gear box. do a search on the bb on this.0
use only redline 85w90NS the NS is a must,
you may need to run it for a while and change the oil again to get out the bad oil.
but I would say take out the LSD after you drane the oil. It comes out very easy and you can leave the box installed. You just need to take off one half shaft and the break disk and caliper. Then check for lose or busted bolts. And open the LSD and look at the plates most of the time they just need a good clean with a sandblaster.
If you can get 2 extra plates before you do it you can do the mod for more lockup at the same time. The how to's are all over the bb if you do a search.
 

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Discussion Starter #3
oil for LSD will kill the gear box.
Why do you say that?
Doesn´t the 75/Milano has a LSD?
All machanics here say that if my car has a LSD I must fill it with some oil compatible with LSD, and if I don´t, the disks will not do the job and and the LSD will not work.
 

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Discussion Starter #4
I checked REDLINE webpage and it says on the "NS" oil that "Also used with clutch-type LSDs in racing for maximum lock up".
So if we dont look to the difference in quality, how the Motul will damage the gearbox?
 

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It is a trade off what is good for the LSD is bad for the syncros.

The thing with most LSD mixes is they have a lot of friction modifiers. And that is death for the syncro. You only want just a tad of the modifiers And Only if the LSD chatters. And no more. The more there is the less the lsd will lockup. So you want to start with none and only add a tiny bit untill the chatter goes away and no more.

I never seen the alfa chatter with none BTW. so none is best for the weak syncros that need all the help they can get. and to get more lockup in the LSD. the alfa box is very picky about it oil and very few oils seem to work at all in the box.

or only 2 the redline NS and the Shell Spirax
anything else the box or the LSD or both crap out.
 
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