Bernies8

I recently changed my transmission fluid with royal purple 75-90w fluid and drove 1000 miles to new orleans, 200 mile b4 i got here it started to catch between 3rd and 4th...Should i change back to factory fluid or try this bg syncro shift fluid i hear so much about? or does this clutch bracket have anything to do with it?

jasonrxeight

MT-90 or factory, I would not use anything else. youre supposed to use ONLY GL-4 transmission fluid. GL-5 is bad.
clutch pedal should affect all gears not just 3rd and 4th.

Bernies8

Thanks.... gonna try the factory fluid and see if it percists but the service manager said that bg syncro shift fluid does wonders for the transmission...

jasonrxeight

buy some MT-90 and change it yourself. service manager will always try to sell you junk.

Flashwing

My god, every time someone posts that GL-5 fluids are bad I'm going to start killing a puppy.

Most GL-5's (I'm sure someone could dig an exception up) are designed to be used in manual transmissions. One such fluid that was tested by BHR was the Eneos 75w-90 and every single RX8 owner that has tried it has agreed it's the best stuff they have tried.

I've personally used every single product in Redline's lineup and while I agree Redline makes good stuff, I believe the Eneos is better.

I ran the Eneos GL-5 in my own RX8 transmission and had two samples lab tested for dissolved yellow metals. There were none. You can see the lab reports here on our website. In total I've got well over 30,000 miles with GL-5 in my factory transmission and I've had no issues and neither have any of our customers.

There have been some issues reported with the Royal Purple stuff. I had some issues of my own that cleared up after changing to a different fluid .

Either way, please stop spreading misinformation about this stuff. It gives me a headache.

Haze

Never tried Eneos. I am sure that Flashwing's assesment is quite good.

I have tried Royal Purple, and ran it for about 25,000 Miles. It wasn't good in the long run or the short run IMHO. Switched to redline, and I have had no problems with over 30,000 miles. Transmission shifted much better on it.

That's all I've got.

dmorales

I've used Redline last time. What about Lucas? I bought some and used it in my dif.
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User24

iTrader: (1)

Sometimes from a stop, if I shift the **** to 1st gear but don't actually get the transmission into 1st gear, what does that mean? The wrong fluid, or do all manual transmissions have that eventually?

jasonrxeight

would it go in or not? if its in then its in, if its not it should go back to neutral.
I had similar problem on my wrangler due to old transmission fluid thin out when its warmed up. the syncro just wouldnt work to stop the input shaft so the blocker ring was blocking the gear to go in. changed fluid and problem solved.

SayNoToPistons

iTrader: (8)

Agreed. Though Eneos fluid might make the transmission louder, it is smooth as silk.

Razz1

Mobile One works great!

RotaryResurrection

iTrader: (3)

Uhm...

You realize that in general, higher fluid ratings indicate equal or (usually) better properties than it's predecessor, and meet/exceed all requirements of that predecessor, right?

For instance...my 02 truck calls for DEXIII ATF. In 06-07 GM came out with DEXVI ATF and changed the specification on all the newer vehicles to that fluid. They've also said to put it into all earlier models that originally callled for DEXIII, because it is a successor to that fluid with all around better properties.

Now if some dude on the internet (or service manager) were to tell me that DEXVI was "bad" for my trans and I should only use DEXIII because "that's what the owners manual calls for" then I would say they are dead wrong and uneducated....wouldn't you?

navyslideby

hmm, dont mean to thread jack, but when ive tried a few times to shift through a couple gears really fast, ive been getting grinding. however under normal driving conditions i get no grinding although i can hear the transmission slightly with the windows up and the radio off. i dont know what fluid is in there now, but could fluid create this problem??? And please do not suggest driver error!

RotaryResurrection

iTrader: (3)

Despite mazda's company logo, these transmissions are fairly weak and are not meant to be driven hard or shifted fast. In fact "shifting mad quick" will get you some dead synchros really quickly no matter what fluid you run. These are also noisy in neutral and at low speed. Some fluids may result in better shifting (or worse) and less noise (or more) but none can change the inherent traits of the transmission design.

So yes, change to some nice synthetic fluid, but don't push the trans in terms of quick shifts. Trying to be Michael Schumacher in your near-stock rx8 won't make it any faster, it'll just tear the trans up. This car is about smoothness.

Flashwing

I'll preface my statement by saying I totally agree.

GL-5 fluid typically has been used in differentials with the early fluids that were released under the new rating. Most (though I think all) GL-5's are now safe for manual transmission use. The reason people have poo poo'd the GL-5 fluids in the past is there was a fear that transmission temps could get high enough to cause the fluid to chemically react and create sulfuric acid.

The temps to do so would be much higher than anything the RX8 transmission would ever see.

jasonrxeight

ok the difference between GL5 and GL4 is basically GL4 has half of the chemicals in GL5.
more isnt always better. why you run 50/50 coolant not 100% antifreeze is for a reason. if the manufacture says its ok, then go ahead. until Mazda says GL5 is safe, Im sticking with GL4.

Munchy

iTrader: (2)

question for the BHR guys, what do you put in your diff if you put eneos 75w90 in your transmission?

i did the redline mt90 for the tranny and redline 75w90 for the diff but im hearing a grinding sound while in 6th gear
i think i'll try the eneos after winter storage and swap out the diff fluid again too...

Bernies8

Replaced the transmission fluid with bg syncro shift it shifts a little easier now and no smell like with royal purple but i still get a little grinding between 3rd and 4th when i try and quick shift but like some of u have said this car is about smoothness and when you dont quick shift it goes in smooth!! but overall it is a good product!!kinda hard to find though!!!

jasonrxeight

grinding noise only in 6th how could it be diff?
besides MT-90 is exactly 75w90

Flashwing

Again, you're making very very general comparisons that have nothing to do with each other. GL5 has a much larger amount of pressure additives. Totally different than the aspects of coolant. Ethylene glycol is not nearly as good of a remover of heat as water is. Sadly, water freezes at a much higher temperature than 100% ethylene gycol so the two are mixed for colder environments.

I'd suggest hitting the books and reading up on these topics because again you're posting totally incorrect information and my headache is starting to creep in.


We all use the Eneos 75w-90 oil in our transmissions. The fluid can be used in both locations.

If you have a grinding noise while in 6th gear I wouldn't bet on the fluid being the issue.

jasonrxeight

Im not saying GL5 is gonna destroy your transmission. my point is if the manufacturer sees benefit of using GL5, then I would switch to GL5. if GL4 works just the same and manufacturer recommends, there is no reason switching to GL5.
mostly GL5 is used in diffs, but transmission is more complicated than diffs. I dont really wanna go too deep into it cuz topic like this usually end up just like discussing oil.

navyslideby

im no michael schumacher, im more of a Keiichi Tsuchiya in the making. but ill keep this as the nice, fun daily/track car and build another beast of a 240sx as a drift car........

Munchy

iTrader: (2)

i think it might be a bearing but either way, i plan on swapping out the oil every year.

laythor

another thread on transmission fluid.. is it that time of year already?

nycgps

iTrader: (1)

well the manual said GL-4/5 works.

I used to have RP Maxgear. it was ok? but from time to time the thing grinds a little. switched to MT-90 never had a problem

I always wanna try Eneos. but MT-90 is working fine for me so far so I will try it on my next change. which is another 15K miles or so.

For the record, (as far as I remember) my 1991 RX-7 also saids GL-5 oil is ok. I know its diff tranny. just sayin'