Plate diff oil to use?


EK9 Matt

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Hi guys, I know this has been covered various times in the past but just wondered what today's take is on what oil+friction modifier to use in a plate lsd. I've purchased a cusco rs diff so just want to get stuff ready for when I install it.

Cheers,
Matt.
 
Is it a track car or road car?

Either way I would recommend to use Torco Mtf or Torco Rtf. You can also use a 50:50 mix of Rtf and Mtf which works very well

For a track car you shouldn't need any friction modifier as it reduces the effectiveness of the LSD and the synchros

For a road car to try and make the diff less clunky you can use friction modifier in small amounts until you get a happy medium


What you can also do with most plated diffs is change the initial lock from 100% to say 70% by switching the order of the plates. This will make it less snatchy/clunky when turning at low speeds. Then you shouldn't need friction modifier
 
Car is mainly used on track, used on the road to get to the track or shows etc.

By the sounds of it then I may just try the torco mtf/rtf and see how it is. Could always add friction modifier after if it's brutal.

It's a minefield on what oil to use as people say 85/90 etc, that's fine in a conventional diff but with ours being inside the box its no good on the syncros like you said above, and I've just bought a syncrotech kit for my box.

Thanks for the reply.
 
Definitely stick to the Torco MTF/RTF

Gear oils are not designed for a Honda gearbox and the viscosity/friction properties are not right for needle bearings or the synchros etc

A gear oil may quieten down the diff but then it's not working as it was designed. A plated diff is hard to live with on the road as it was designed for the circuit so anyone who doesn't want to put up with the heavy steering at slow speeds and clunking should be using a Helical diff
 
Nah I'm all up for putting up with it, as I say it doesn't see the road much. I'll get some of torco purchased then and give it a bash.
 
After you give it a go, try some Amsoil MTF. This worked wonders for me.

I'm using a Wavetrac LSD. My gearshifts are also silky smooth like the k series from using this fluid.
 
I haven't bought anything yet as the car is going in for mapping soon so I'll take the box out after. So I'm still open to suggestions:))
 
Synchro80 is supposed to be decent for plate lsds in synchromesh gearboxes.
 
I would use the diff oil that the manufacturer of the diff recommends, i have a KAAZ plate diff and i have always used the KAAZ oil 80w90, and that would last me about 12-14 months with no problems no loud noises and no problems changing gears etc... on the odd occasion i cant get the KAAZ oil i have used castrol Diff oil of the same grade 80w90 and after about 4 months it needs a change as the diff will make all sorts of clunking, and once a garage used normal gearbox oil even after i expressed my concerns about oil choice, the normal gearbox fluid lasted about a week!
 
When we(me and previous owner) first fitted the kazz diff in his car(now my car) we used the kazz oil. Totally killed the diff, almost like a stock diff really. Previous owner said it was harder to shift whilst cold(was a really cold day). We chose to put up with the clunks and snatches at low speed for the diffs capabilities on track at higher speeds with a different oil in.
 
Not much info out there on what oil cusco recommends. Its a different ball game in a FWD as the diff oil also has to be syncro friendly, where as in a RWD the diff is on its own in a separate casing, it will always be a compromise unfortunately.
 
I used redline (mtl I think) oil with friction modifier with my cusco diff, it was pretty much all I could get hold of at the time that was suitable.

Apparently the m factory diffs are almost identical to the cusco's, they recommend torco if I remember correctly
 
Yeah that's right, mfactory basically copied the cusco design.....good point, they do recommend torco;).
 
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