I can pick some of this up at the shop where I work. It is a full synthetic and is rated 75w140 GL-5

I was wondering if this is a possibility for replacing the fluid in my tranny?

Anyone know what the difference is in the GL-4 and GL-5 lubricants?

I really can't forsee any problem in running a heavy oil like this because its cold temp weight is low but the high temp weight is high.

Here's some in-depth info that I don't know how to properly decipher.

Oil: 75w 140 GL-5
Color: Red
API Gravity: 31.3
Viscosity at 40 oC, cSt: 186
Viscosity at 100 oC, cSt: 25
Viscosity Index: 172
Pour Point oC: -45
Flash Point oC: 206

Energy efficient, low-drag formulas for unparalleled gear and bearing protection: Tremendous lubrication protection in extreme heat conditions
Dramatically reduced drag at all temperature ranges
Energy efficiency
Reduced wear
Unparalleled oxidation stability
Easier, smoother shifting
Total protection of gears and bearings
Extended component life

Some quotes from the manufacturer.

 

In case you are wondering on the company, it is Golden Spectro

they advertise their products can be used in ATV, Motorcycle and automobile applications.

The only downfall to the heavy oil is some power loss, according to Spectro's page. They say it is good for race applications where maximum power isn't necessary.

I think this may be a little too much for my RX, but I would like someone else's input too.

 

everyone here swears to royal purple

 

Golden Spectro makes some EXPENSIVE lubricants for motorcycles.&nbsp Did you try and open and smell the fluid?&nbsp If it reeks, you can't use it in the trans.&nbsp I was going to ask if it specifically mentions you can use it in the trans, but you did state that the bottle claimed "smoother shifting"...


It's a bit heavier weight than recommended, but it makes for better lubrication...


-Ted

 

Icemark made some good points. One thing to watch ou for is GL-5 had sulfites that raise hell on Rx7's syncro's. GL-4 doesn't have these Sulfates, GL-5 does.

Kind of another angle to the if the smell "reeks" test. Sulfates are pretty stinky.

 

Thanks for the replies. I will prolly just avoid the whole thing. The bottle claims it is good for auto tranmissions, but the bottles have the perforated ring around the cap to tell if it has been opened. I don't feel like raising hell at the shop just so I can smell the stuff.

I will stick with either ordering some Redline or Royal Purple.

 

Oh, ATF and manual trans fluid are two different beasts!



-Ted

 

Ted,

I didn't mean ATF with the auto transmissions comment. Should've been a little more specific with my writings.

I meant that it is alright to use in "auto"mobile transmissions, as in a 5-speed in this case.

 

Mazda(1991 RX7 shop manual) recommends GL4 or GL5 in 75w90 or 80w90 weight.
If OEM can recommend GL5, then the transmission has been engineered for the added sulfur/phosphor content.

All gear oil smells. I wouldn't use a smell test.

So, who out there had a synchro wear problem using a GL5 gear oil? Can they prove that it was caused by the gear oil? or lack of maintenance? or poor driver shifting?

I have used GL5 for years in several cars and never had any premature wear.

 

Redline MT-90 (and MTL) isn't as bad as Redline 75W90 or any other "gear old".&nbsp Sulfates in the fluid make it smell "bad".&nbsp Transmission fluids should NOT have sulfates in them, as the sulfates "eat" the brass synchronizers.


-Ted

 

So whose right? Can I put gl-5 or not? It does recommend it in the service thing.....

 

Anyone have experience with amsoil I read a study by them but that's what make me iffy about it. Their gear oil did good on all the test but they wrote the article, which also shows that royal purple and Lucas oil aren't all that great it's a pdf file on Google if anyone wants to look it up.

Also the study was done in 2007 not sure if that makes a difference.

 

redline and never look back

 

^ what this guy said.

 

would like to know the answer to this as well?

 

The factory service manual specifies either GL-4 or GL-5. However, I have had best results with Red Line MT-90 GL-4.

 

depends on if its a n/a or turbo, the turbo trannies aren't very happy with heavy gear oils and quick gear changes.

 

140 weight sounds like a wee bit too much for our little RX7s... Unless you're towing boats with it or you have a habit of blowing up differentials while endurance racing and don't mind power loss. Stick with a 90 weight and enjoy the extra gas money! Also to note is that many synthetics typically have smaller molecules overall from having tighter variations in size, so you may see a 90 weight synthetic flowing like a 85 weight dino (if such a thing exists commercially). So maybe this 140 weight synthetic isn't so bad.

If you bail on that Golden Spectro, I'd suggest Neo Synthetic 75W90HD. I admit that I don't have any real reference outside of it, but putting it into a friend's '84 GS made it feel as silky as a new MX5. I also use it in my '87 Turbo-II, same story. Neo is terrible at providing info about their oils, so I've no idea if it's GL-4 or 5. It just says that it's compatible for applications from GL-2 to 5, and some GL-6 applications. Ok, thanks. I picked this oil over the Royal Purple on my shelf because word of mouth on this forum said it was nice to synchros. I feel like it is. Take it for what that's worth to you.

Otherwise, I'm sure you won't go wrong putting any name brand oil into it. You just need to be mindful that fresh oil is fresh oil, not a bandaid to an ailing transmission. Some people here are coming to look for snake oil and complaining when it doesn't do magical things.