Ive got a redline cocktail in mine. First i had crappy 140 weight in it (dont ask was all i had was when i first got the car didnt know any better) had bad syncro problems (they were bad when i bought the car but this made them worse, toke forever to go into gear/ wouldnt go when cold.) I then found the forums, draind all that crap out and put in 75wt90 redline in it, much better but would still snag if i shifted fast. Had a clutch go bad, replaced with 50% used 75wt90 and 50% MT90, worked good only really fast shifts would grind. Put a lightweight flywheel in added about a quart of heavy shockproof to the mix,.. now its just about perfect,..

so i recommend 75w90 mixed with 90 mixed with heavy shockproof,.... which probably comes out to something like lightweight shockproof like Icemark said,..

 

That's some expensive fluids you're experimenting with!


-Ted

 

From what the guys at redline and various other resources say, they say to use REDLINE MT-90 for the transmission. So I would probably stick with that. Remember that the RX-7 is a sports car and not a cheap honda or toyota, so dont treat it like one. Quality parts cost quality prices... unless you have the hook up.

 

must save for mt-90....
$11 a bottle here at autobacs!

Oh well its worth it!

 

what fluid are you guys runing in a LSD rear end

 

I ordered my Redline mt-90 tranny fluid and diff fluid (forgot the type) from summitracing for about $7-8 each bottle with free shipping. There was some small service charge since they were hazardous materials but still cheaper than $11 each.

 

What red line oil do you guys think is best for the diff?

 

I think I ordered the 75w90. Havent had a chance to change the fluids yet since I have other problems to figure out so I can't comment on which is the best. I believe most people say:
mt-90 for tranny
75w90 for diff (I think Icemark prefers the shockproof lightweight one)

 

So moblie one sythetic is actually bad for our trannies?
There should be a warning label some where about that like the one under the hood that says not to put sythetic oil in our engines.

what about Royal Purple or even Lucus???


my question is if the sulfur does eat up our synchros like you guys say how does it break apart from the massive gear oil particle, in large enough quantities to even matter...

could it be that there is another chemical that when broken apart actually cancels this charged particle out....untill someone shows me the synchros from a tranny using moblie one next to synchros using redline, I'll remain a skeptic....till then I hope I don't find out on my own...

 

Sulfur is one of the more corrosive elements out there, it does eat through brass and bronze and any other of it's alloys quit easily, the only reason it's in oils is because it's very good at stopping other things from reacting at high temps, it's in your gas and what not, very low quantities but it's there. Also it would not need to “break away” from the oil particles, it’s not part of the actual oil and neither are all the other additives, they are additives mixed in to tweak the properties of the oil. For example, let’s say you start passing 02 bubbles through the trany oil, over time you would get sulfur dioxide gas being released. And as we know oxygen is not corrosive so it’s not pulling away the sulfur, the sulfur is pulling away the oxygen molecules. I'm guessing why it's in run of the mill synthetics and gear oils is that probably newer cars and older non top of the line cars don't have brass syncro's, and they expect us car enthusiasts to know better. True I'm just learning about the brass syncro’s but I haven’t changed my trany oil yet... heh now I know what to use. But I’d trust the judgment of the guys who work on these cars a lot more than we do.

 

I've had Mobil 1 in my tranny for about a year now. Still shifts better then any other RX-7 I have ever driven.

However, I will eventaully shift to MT90, because you guys are right; sulpher does eat brass, we have brass synchros, and Mobil 1 has high sulpher content.

 

I use Royal Purple Max Gear for the tranny. Fantastic stuff! It shifts better than when I had Redline MT90 inside. Anyone who's thinking about the Royal Purple, go for it, it's some good stuff!

As for diff, I have heard Shockproof light is good. I use Redline 75W90 right now, but have tried the Shockproof light in my wife's WRX before, can't really tell the difference.

BTW, bad experiences with Amsoil Series 2000 75W90 (a.k.a. smurf juice), I think it's just too darn slippery, but their engine oil kicks *** though.

 

Oh, BTW, the bad experience with Amsoil is with the Series 2000 75W90 in the tranny, not diff. Thought I clarify.

 

I've had great luck with pennzoil syncromesh. Quieted down scratchy synchros in last 7's I've had, shifts smoother, too. Get it at any autozone ($3.99), same stuff is sold at GM dealerships for $10 a bottle.