Transmission fluid: Redline vs Royal Purple
 

Who's used them, I've heard nothing but good stuff about both so now I dunno which I should run heh.

Redline shockproof vs redline non-shockproof vs Royal purple synthetic?

Going in an S4 TII tranny and dealing with 400+ hp.

Trying another stock trans? :)
I would suggest you get a carbon clutch this time!


-Ted

I had another S4 TII trans laying around
and I want the car on the road like, now. Yuppies with supras to deal with. :P

I actually have a reasonably gentle clutch - an ACT 2600.

I just want this transmission to last longer than two weeks heh.

Although I can't say anything about Royal Purple tranny fluid, I can say that I use the synthetic engine oil in my FC, and it does a terrific job.

A fellow rotor head here in raleigh has used redline in his fc tranny for the cars entire life. It's a stock 86 GXL w/ 165k on the clock and the tranny is smooth as can be.

For the stock tranny use Redline MT-90, it's what's reccomended for them. I use it and it's good stuff. My tranny had a 2nd gear grinding issue when using conventional fluid and it doesn't any more. I can't say whether Royal Purple is better or worse, but I do know that I only see Redline at the races.

I read through a bunch of forums when picking my tranny oil. Some made for easy shifting, some reduced or eliminated grinding. Only Royal Purple and Neo did both. Redline made shifting easier, and I'm sure it's about as good (and cheaper) on the race track, but users said grinding stayed the same or got worse. Supposedly Royal Purple gives slightly more horsepower than anything else as well, from less friction.

I happened to be making an order from Mazdatrix at the time, and they only have Neo tranny oil. So I'm running Neo now and it shifts as quickly and easily as a child's toy (it didn't before). It won't grind either. Even if I mis-shift it goes <clunk> and bounces off, but it could just be my clutch/tranny is in good shape.

if my car has never used royal purple oil for the trannywould it cause any harm?? same with the engine... would that cause any harm?

Im not running any crazy power like you. But, I run, and Love Redline's MT90 in my 89 N/A.

i use Royal purple in my tranny and rear end and love it a little cheaper than redline... but i also had a 2nd gear grinding and 3rd gear when i put RP all of it went away and throws were alot smoother...
TwEaK

i use syncromesh in my n/a.. got rid of grinds, and i can acutally get it into 3rd at 8k... anyone else use syncromesh? what do u guys think of it?

Synchromesh is too thin and will not protect the transmission.

Redline MT90 is thinner then RoyalPurple Maxgear. No way does Maxgear work better in cold. Its too thick. But, thick=protection so it might protect better. And, thick=power loss.

Redline 75w90NS should protect better then their MT90.

Shockproof heavy might protect the best. But, you'll have to test the shift quality yourself. Some trannies tolerate it. Others don't.

Don't expect a fluid to make up for bad shifting habits or too much power.

I use the Redline superlightweight shock proof in non turbo trannies.

From Pegasus racing:
But for turbo trannies is use light shock proof:
Redline MT 90 also works well, and is the old Redline MTL but meets the GL4 requirements (as our trannies require)

RP has a specific tranny oil and its super thin like 10 weight.

I have ran it its ok but I realy do not like it that much. I prefer to run the RL tranny oil and I run the RP max gear for the rear end as it has an LSD friction aditive in it and well therfor wouldent be recomended in a tranny.

+1

Please stop making dangerous comments like this.

75W90NS is a GL-5 gear oil that contains sulfates in it.
Sulfates will corrode the brass synchronizes in the transmission.
This is BAD.
It will cause the transmission to start crunching during shifts.

MT90 is the recommended fluid for the FC transmission, period.
The Shockproof oils can be substituted.
You can call Redline 1-800 tech line.


-Ted

Best info yet, though someone was correct in saying some transmissions/rear ends don't seem to like shockproof. The rear ends in cars I've ridden in w/shockproof were noisy as hell compared to mine w/regular synthetic.

Run a search on "NEO transmission" and see what people have to say about that stuff. ;)

Here's one thread:
https://www.rx7club.com/showthread.p...o+transmission

Not a dangerous comment, just Lube 101
 

All transmission fluids contain sulfur. Gear oils are buffered to prevent these issues. And, many now use inactive(vs. cheaper older active) sulfur additive packages. GL5 gear oils ARE just safe as GL4 gear oils when not pushed beyond it service life.
Sorry REted, but all that GL5 eating synchros is one of those FEARS that has been overly hyped by the internet!
A GL4 gear oil that has been oxidized and whose additive package is depleted is very corossive and will also eat your synchros. Yet, we all blindly push GL4 gear oils without understanding why. Any fluid pushed beyond it service life is destructive, regardless if it is a GL4 or GL5.

Some of these GL4 manual transmission fluids are surprisingly blended very stoutly(as seen in a virgin oil anaylsis), with a GL5 level or higher additive package. Usually the thinner you go, the more AW/EP additives you want to make up for film thickness reduction. But, these GL4 manual tranny fluids are smartly marketed ONLY as a GL4 even though they have very stout additive packages. Marketing tends to cater to the brainless mass of consumers. I know of 2 high end boutique GL4 75w90 gear oils, often mentioned and recommended, with additive packages that would shame a store bought generic mineral GL5 gear oil. That alone should put the higher/lower sulfur argument to rest.

Those bad synchro eating acids formed by the sulfur is caused by fluid oxidation, moisture, and other fluid breakdown related issues. These issues are easiily prevented by changing the gear oil at a reasonable interval. But lazy and cheap RX7 owners don't want to change their gear oil every 2-3 years or 30k miles. Those that don't maintain their transmissions will have issues REGARDLESS of gear oil used.

Note that I don't recommend just any ol' GL5 gear oil. Redline, Motul, Amsoil, Specialtyformulations, RoyalPurple, Neo.....have GL5 gear oils that are recommended and safe for manual transmission usage. I didn't go out and recommend any generic mineral oil that is quick to break down or with a discount addtive package, typically installed by the local jippylube, garage, or cheap ignorant Rx7 owners.
I recommend higher end synthetic based boutique gear oils that aren't 'cost' challenged and typically use the better buffering agents and inactive non corrosive additive packages. These boutique gear oils also used basestocks that do not oxidize quickly and can take the heat/abuse that mineral gear oils can't.

Besides the discount no-name gear oils, the only other problem with GL5 gear oil is that most over the counter gear oils are blended with LSD additives. Any OTC gear oil pre-blended with LSD additives should be avoided in any synchronized transmission. The LSD friction modifiers hinder the synchros ability to work and will lead to poor quality shifting(notchy shifter or crunching gears). At the local autoparts stores, just about every GL5 80w90 is blended with LSD additives. This is the reason why so many have worse shifting with them.

According to my owners manual and factory service manuals, GL4 OR GL5 gear oil can be used. If Mazda isn't afraid of the GL5 additive pack(see how vocal they are against synthetic motor oil), then why should you be?
And, does anyone want to guess what the factory fill is that some of you still are using after 15+ years?

For most people, I will always recommend a GL4 gear oil. Its an idiot proof option since there are only few that are available, none have LSD friction modifiers, usually are synthetic(don't break down quickly), definitely shift the best(lack of LSD additive and blended thinner), and will tolerate that poor maintenance intervals.

For those that want better protection, I'll always recommend a GL5 gear oil LABELLED manual transmission safe or are dual rated, GL4/GL5. These will protect better(GL5 additive pack) and tend to be a little thicker(film thickness important in tranny). You might sacrifice a little shift quality, but that depends on transmission condition and shift style.
My 16 year oil transmission will shift perfectly with ANY gear oil. But, cold overnights make the RP & M1 a little more notchy(but still better then the factory OEM fill from year ago).

Redline Shockproof is best for those that need it. This additive overdosed syrup is a racing fluid. Its best for those looking for a bandaid for a weak transmission or rearend, and for those that disassemble and inspect their components regularly. Problem with shockproof is that you should pick the one that works best. And, I don't see it as an optimum shifting fluid. I also don't care for the 'plating' that I've seen with the Schockproof. It seems to buildup, possibly from the megadose of additives. I'll surmise that the plating buildup, is how it protects.

And, I don't see any fluid as a fix for a broken or weak transmission. Fix, rebuild, and upgrade for your intended usage.

wow

I've learned quite a bit about transmission fluids here now, wow.

Thanks for all the info everyone!

I went with the "Royal Purple" 75w90. It's even purple fluid. Oooh. (it better be since it cost me $40 to fill my tranny!) I'll update this post if I ever have any further transmission issues, though I am not exactly using the transmission for it's design spec (like an extra 2000RPM and extra 250+hp being put through it) so I'm sure this isn't the last time I'll have the tranny out of the car. Also, it's got the LSD additive in it so I don't think it's the "optimum" solution anymore... but their claims are pretty nice so I should see!

I've seen it done with my own eyes.
I can't even count the number of times I've come across an FC owner who threw regular gear lube into the trans and complain why it was crunching all the time...
I guess the catch is that the fluid (GL-4 or GL-5) will explicitly state that it's okay for use on "modern synchromesh transmissions".
Not all of them state this.
I have never seen a GL-5 rated fluid that's okay for use in transmissions.
Anyone know of any?
All the transmission fluids I've come across were just GL-4 rated.

GL-4 versus GL-5 is just a gear-load rating.
Nothing more; nothing less.
It doesn't imply anything about being capatible with bronze synchronizers.
Sulfur is used to increase the load-bearing capacbilities.
You can smell it when you open the bottle up.
If it's smells stink, don't use it in your transmission, period.
I dunno if it's a buffer or sulfur is not added, by GL-4 fluids that are made for transmission use do not stink.

I would never throw Redline 75W90NS into my transmission.
In fact, Redline tech will tell you the same thing.
This is what you claimed - this is what I was bitching at.
If Redline tech says don't do it, I dunno why you want go against their recommendations.
This is not some Internet myth - you are just plain wrong.


-Ted

heh

I've been using GL-5 all this time, I thought it was the shit I was suppossed to be using.

The smelly stuff, yeah. My transmissions have always shifted fine though. *shrug*

Royal purple seems to be working well! It also doesn't stink.

I always avoid smelly motor oils - generally it seems to me that only the really quality ones don't smell bad.

Slightly off-topic... is this the fluid that is supposed to go into our LSDs? Not sure if I've been told the right info.

"75W90" is the proper fluid if you're running the stock clutch-type LSD.
"75W90NS" is the proper fluid for *NO* LSD.


-Ted

Good choice.
Drop Redline and go RoyalPurple.

Any thoughts on Mobile1's Full Synthetic Gear Oil?