Gear oil + slipping modifiers = ok.
Mixing a whole bunch of diff fluids = not ok.

Why not add some maple syrop and stoli while you at it. I am sorry but i think it is stupid. Companies have invested millions of dublons into R&D and came up with a perfect fluids for each applications and here we come trying to make a Cosmo out of gear oils.

Motul gear oil FTW.

 

I totally agree. There are many different companies to choose from, redline, penzoil, mobil1, royal purple, lucas, you cant go wrong!. But mixing a bunch of diff. fluids together isnt a good alternative. I have a good alternate route if you want a better gear oil....Use Mopar ATF+4. It has solved alof of manual transmissions synchronizer related prolems in my experience, and is probably the most slippery gear oil available. Find it at your local Dodge dearlership its about $5 a quart too...=). The reason why nobody uses it is because everyone thinks its only for automatics. But if you read the back it says for manuals as well. Just my .02

 

Correct me if im wrong, but isnt that what adding the syncromesh is?

 

AFAIK, Synchromesh is not an additive. Its a standalone gear oil. Slip modifiers come in tiny little bottle are are made to be blended with PROPER gear oils.

I think everyone knows that for engine oil, for example, you can not flip flop from non synth to synth and back to non synth. There is a reason for that, right? Now, if you are purposely mix synth and non synth and fill up the tranny with it. That would be not good. Sure, there are off the shelf blends, but they were not mixed in the garage with a blender.

Anyways, what I said is purely my personal opinion. It is not a fact. I would never put a "cocktail" into my tranny. Especially knowing that Subaru trannies are very fragile. So make your own decisions when it come to this one.

 

Alex, what do you recommend for the STi 6MT?

What about the R180?

 

+1 as I would like to know what everyone uses. I'm about to fill these two up. I've heard people recommend Redline MT90 for the tranny and Redline 75/90ns for the r180.

-Dan

 

You've been hanging around Zoeb too much. :rotfl:

But in all seriousness, there seems to be a lot of confusion over what works, especially with the different Redline oils. My buddy has one of the Redlines in his 5MT and it looks like molasses. I'd hate to have to drain it down the road. I ran RP in my WRX and wasn't too happy with it and I don't want to put something that doesn't work in the STi.

 

Haha yea I had to get up early for class today Must have other things on my mind

Yea thats one reason why I never changed the tranny fluid on my stock 5MT. I was going on 40k before i removed it from the car and it was perfect. No grinds or anything and it shifted so smooth. I never wanted to change the fluid as I kept hearing mixed reviews from people. Now theres no fluid in the new parts I have so I have to fill it with something but I don't want to put something in that will have negative effects on the syncros.

-Dan