Important note about manual transmission oil/gear oil

[Young Roids]

Here is the story. I decided to change out my transmission oil with synth. So I bought 75w90 gear oil that was gl-5 *WRONG!* For transmissions you need gl-4. GL-5 is not backward campatible to GL-4 because it has a sulfur additive. Sulfur is corrosive to yellow metals so eventually it will eat away your synchros. So I realize my mistake and go to buy some gl-4 oil. I went to four autoparts stores and none had any gl-4 all they had was gl-5 and all the employees had no idea that gl-5 was bad for your tranny. Then I do some looking on the net and there are only two brands that have 75w90 gl-4 redline and amsoil. So finally I found a local place that had the gl-4 redline oil A little subaru performance shop named http://www.grimmspeed.com/ So if you are looking to change your transmission oil check them out they are in st paul. I hope this may have helped some people out so they will not make this mistake like I did.

 

[dmention7]

Hmm, good to know. How much did they charge for a quart of redline? Last time I bought some, it was $12/qt with free shipping from streetunit.com

 

[Young Roids]

$10 a quart

 

[dmention7]

Looks like that's what MAP charges, and they're a forum sponsor. So much for SU's free shipping... lol

 

[Young Roids]

OK, yea MAP carries MT-90 as well.

 

[dmention7]

So, how did you learn that you bought the wrong stuff to begin with? Also, what brand was it out of curiosity?

 

[ij1889]

good to know ive been thinking of putting synthetic transmition oil in rexy, hows your car?

 

[Young Roids]

I noticed the car had hard shifting especially when it was cold so I looked into it and found out all this info about it. It was amsoil severe gear 75w90 gl-5.

ij, yes I remember thatyou were thinking about changing your trans oil. The car is good now shifts are good again.

 

[upgtx]

I love redline products, they are all I used in my tranny's/differentials, you can get them online for ~$8.50 a quart or so shipped if you find the right site.

 

[ZoomZoom Diva]

According to Mazda, GL-4 or GL-5 oils can be used with the manual transmission... at least for the Mazda6s. Is this false or is the concern for older models?

 

[Young Roids]

I have the MS3 and as far as I know any transmission with yellow metals in it is gonna be bad with gl-5. So that is basically all transmissions in passenger cars that have yellow metals. To my knowledge the only trannys that do not use yellow metals are the ones found in semi trucks.

So I would deffinently stay away from the gl-5 in your 6.

 

[ZoomZoom Diva]

I hope there is another option, because I have seen too many problems to trust Redline. I will say I had the dealer change the tranny fluid and the shifting has been stiff. I assumed it was just the extreme cold.

Why would Mazda recommend GL-5 in that case is the other question...

I would also be interested in seeing your source materials, as this is the first I have heard of it.

 

[upgtx]

I have never seen any problems with redline, only improvements actually...

 

[dmention7]

+1

I've used redline in a couple different cars, and have had and heard about only good results.

 

[Young Roids]

Yea there is another option. Amsoil makes a gl-4 (amsoil manual transmission & transaxle gear lube 75w90 gl-4). Now that you will have to order on the internet off their website since I am pretty sure that no one carries it locally. If it shifts really hard in the cold that could be the gl-5 since that is the symptom mine had with gl-5.

P.S. as far as why mazda would reccomend a gl-5, that I don't know. was this a dealership or was this from a corporate thing from mazda directly? If it was a dealership then they probly don't know what they are talking about, just incompitence probly.

My source material was stuff that I found searching the web I will try and dig it up again. I did find multiple sources that all said the same things about gl-5 being bad on the synchros.

 

[Young Roids]

Here is one spot that mentions it, http://www.eng-tips.com/viewthread.cfm?qid=120197&page=1



I will post more sources as I find them

 

[Young Roids]

http://www.nissanforums.com/b14-95-99-chassis/104196-gear-oil-gl-4-vs-gl.html

here is a forum discussion about the topic.

 

[ZoomZoom Diva]

P.S. as far as why mazda would reccomend a gl-5, that I don't know. was this a dealership or was this from a corporate thing from mazda directly? If it was a dealership then they probly don't know what they are talking about, just incompitence probly.

Owner's manual for both my Mazda6 and my RX-7. I am looking at the posts... I'm not trying to argue, but I'll admit to wanting more info.

 

[Young Roids]

Hmmm, that is puzzling to me. Maybe the mazda brand gl-5 doesn't contain sulfur? I don't know really. I will try to look into it.