SteveSAS

Hi Guys,
Just joined this forum as an EVO 8 owner from the UK.
I've been reading some posts on here with interest regarding oil choices for Transfer case & rear diff.
I have seen most of you prefer OEM Diaqueen 90LSD for both, but have also seen some tests the fully synthetic 75w90 plus oils.
I currently have Motul 90PA in both T Case & Diff but am due a change. Do I understand correctly that this 90PA is the closet in spec to Diaqueen?
Here in the UK most use either Motul Gear 300LS, Fuchs Titan or Millers oils. All these are fully synthetic 75w90 GL5 and good for LSD.
I like the fact that these oils are Full Synthetic rather than mineral like 90PA or Diaqueen & also there is a thinner cold viscosity (75) & surely it should work better (like it does in transmission & engine) than a one viscosity mineral oil?
Mitsubishi don't even use this here in the UK for their servicing. The only Diaqueen stuff they use is the SP111 for the AYC.
Now, I have read that some see the 75w90 as a bit too thin compared with the OEM 90 spec. I don't use the car hard on track & is only mildly tuned.
Would Redline 75w110 gear oil be the ideal option for a full synthetic oil that is close to OEM 90 viscosity?
Anyone on here have experience with it?

Thanks
Steve

kaj

iTrader: (60)

We don't have AYC rear diffs here, so possibly use a different fluid?
I am curious, though, as I have a Cusco RS rear diff for AYC so am thinking about buying an AYC pumpkin and axles so.I can use it (as opposed to.collecting dust in my garage).

Evo9isLife

Oem Diaqueen is always a safe bet but Motul Gear 300 and Redline are slightly better. I always use Redline fluids, specifically 75w90 as I do not track my evo. 75w110 would be ok too. The more relevant viscosity number to look at is the 90 in 75w90. The second number is the viscosity at operating temp so they are basically the same. I would bet that Redline 75w90 is slightly thicker with a better HTHS at temp than oem 90.
Edit: When you say they use SPIII you are referring to the ACD/AYC reservoirs and not the actual diff right? SPIII is an automatic trans fluid..

SteveSAS

Yeah, the SP111 Diaqueen for the AYC reservoirs is the only Diaqueen Mitsubishi still use here. They use lubricants from a UK company called Morris now & I believe the diff oil is an 80w90 weight.
I was just curious for peoples views, as I have read forums from here where people stick with OEM Diaqueen & think using anything else is a risk.
I have gone with Redline MT85 in my transmission & Motul Sport 5W40 (ester) in engine.

Thanks