Concerned with MT90

[ericm979]

Originally Posted by AutoXRacer Never ever add friction modifier to a synthetic. That is to be used with dino oil!!!! Friction modifiers are for friction (clutch) type LSD...being used with dino oil. The modifier is like concentrated synthetic fluid. When you purchase Red Line or any other "true" synthetic gear oil and/or tranny oil, it does not require any other additives!!

Not according to what I have found while researching this. Amsoil's GL-4 synthetic doesn't have friction modifier at all (per email from amsoil tech support), and they sell one to address that. Redline sells some formulas of synthetic transaxle oil (the 75w-xNS ones) that have no friction modifier. The data sheets for those explain how to "tune" the LSD by adding small amounts of friction modifier.

The regular MTL and MT-90 do have friction modifier.

[AutoXRacer]

Thats exactly what happened to me... A long time ago, I used to be an Amsoil fanboy, until I tried it in my tranny... Shifting was worst than with the stock fluid...so I tried Red Line...it was smooth as butter. So, I figured if Red Line was much better for trannys, maybe it did the same for engines...

So here I am quite a few years later, full Red Line fluids in my MS3...

I never had any issues with Amsoil motor oil...just their tranny and gear oil sucks!!
I like their oil filters though!!

[crypt0wind]

I think people are confusing what the problem with GL-4, GL-5, synthetic or dino gear oil . It has nothing to do with shifting smoothness or normal gear noise. It has everything to do with a noise from the LSD when turning at low speed. The lowwer the speed the more noticeable the noise. I describe the noise as "wah wah wah", it happened to me with synthetic gear oil.

Brand and rating of gear oil are important, but not the key to be "wah wah wah" LSD noise free.

Friction modifier seems to be the key. A gear oil with friction modifer (included or added) seems to work no noise. A GL-4, GL-5, synthetic or dino gear oil without the friction modifier the LSD makes the noise "wah wah wah", but still shifts smooth.

[Zeya]

Hmm. People like the penzoil platinum motor oil. How about their gear oil?
Products - Synthetic Gear Oils 75W-90

[crypt0wind]

Originally Posted by Zeya Hmm. People like the penzoil platinum motor oil. How about their gear oil? Products - Synthetic Gear Oils 75W-90

I'm just guessing, but I'll bet you will hear the low speed "wah wah wah" LSD noise with the Pennzoil.

GL-4 - Nothing about LSD or a friction modifier added
http://www.pzlqs.com/Tech/Pdsheet/Do...E75W90GL-4.PDF

GL-5 - "PENNZOIL® SYNTHETIC SAE 75W-90 GL-5 is suitable for use in both limited slip differentials and conventional axles. It may be used for makeup or complete refill of limited slip differentials, including rebuilt units." Just because it says suitable doesn't mean it has the extra properties our LSD requires for noise free operation.
http://www.pzlqs.com/Tech/Pdsheet/Do...E75W90GL-5.PDF

Again it would shift smooth, feel good, but have the low speed LSD noise.

[enganear]

This must be the 6th time I have explained this. The noise is the high frequency stick slip from the cone type limited slip differential. You will hear it the most when cold and turning high lock at low speeds. You will hear it more with MT90 because the same shear resistant properties that improve the operation of the synchros result in a slightly grabbier lsd operation.
If you add friction modifier you will reduce the sound and you will also reduce the effectiveness of your synchronizers and lsd. Did you buy a performance car or a Cadillac? The sound hurts nothing and I smile every time I hear it. I am constantly amazed at the number of people that will open their exhaust and vent their blowoffs to atmosphere and then complain about normal sounds from their performance lsd.
-enganear

[Zeya]

enganear: I hope you aren't bagging on anyone in this thread, because all I see are people who are concerned about a strange noise after a fluid swap and want to make sure they haven't messed up their ride.

[yager]

sub

[gtlaw]

I never even noticed the sound before or after MT90, but I mostly drive a sentra that sounds like a renegade dumptruck so the ms3 seems quiet as a rolls royce to me

[bacarl]

Originally Posted by Zeya enganear: I hope you aren't bagging on anyone in this thread, because all I see are people who are concerned about a strange noise after a fluid swap and want to make sure they haven't messed up their ride.

^x2

However that being said, I really appreciate your input enganear. I know that you're a knowledgeable guy and as such it can be tedious explaining things to those less knowledage. Esp over and over. I for one was not aware of the stick-slip condition; I wasn't even certain what type of LSD our cars were equipped with! Like Zeya said I just get paranoid when I hear a noise that I don't recognize that isn't supposed to be there. I'm also an engineer (albeit a very young one) and I know the exacting standards to which cars are built and how easy it is to mess them up.

Thanks again for your input, man.

[Funky]

Oh this thread is so life saving! I just about pull all my hair out when making a turn and hear the annoying noise.

The only thing is, my reverse almost ALWAYS grinds since I've gone with the MT-90... And I haven't felt ANY change in shifting... Kinda dissappointing. I at least hope my Tranny's happier...

Funky

[enganear]

Originally Posted by Zeya enganear: I hope you aren't bagging on anyone in this thread, because all I see are people who are concerned about a strange noise after a fluid swap and want to make sure they haven't messed up their ride.

Apologies to all. I was in a pissy mood and should not have posted.

I played a lot with different LSDs back when I was autocrossing a 5.0 Mustang. You think a MS3 diff is loud, you should hear an Auburn cone clutch diff at low speeds and full lock! I eventually settled on a Torsen gear-type LSD, not because of the cone clutch noise, but because of the reduced effect on turn in - less static friction. LSDs that use multi-plate type clutches need the friction modifier to avoid extreme and damaging chatter at the plate teeth. Other LSD designs do not need this. The well lubricated steel-on-steel cone clutch used in the MS3 can go wooooooo all day without any damage, but the fact is there is very little relative motion of the faces under most driving conditions. You will likely hear the sound more with MT-90, I know I did. I only notice it pulling out of my drive in the morning. I am very pleased with the shift quality after changing to MT-90. Before MT-90 I could easily outrun the synchonizer when shifting to 3rd. MT-90 fixed that for me. YMMV.
-enganear

[Zeya]

Originally Posted by enganear Apologies to all. I was in a pissy mood and should not have posted.

It's cool, we've all been there. You obviously know quite a bit about what you're talking about.

I'll chime in on this subject since a week ago I did a trans fluid swap to the Redline oil. It feels and sounds almost exactly the same to me. Of course I don't have the keenest ears in the world either. The low speed transmission noises sound the same to me as before. I'm willing to bet some people are just listening a little too closely and psyching themselves out. The redline oil feels slighly different, with respect to shifting, and a little easier to move the stick into place, but that's not this thread topic...

[Funky]

so do you guys think its actually the synchros that make my reverse grind almost 30% to 40% of the time? I'ts only been doing that since MT-90...

Funky

[enganear]

Originally Posted by Funky so do you guys think its actually the synchros that make my reverse grind almost 30% to 40% of the time? I'ts only been doing that since MT-90... Funky

The MS3 has an unusual transmission, but I have never seen a transmission that had synchros on the reverse gear. Come to think of it, I have never gotten any grind or even a clunk out of shifting into reverse....

Try putting the stick in a forward gear first to let the synchronizers stop any motion in the transmission. Make sure the car is stopped, and then shift into reverse. Never shift into reverse with the car rolling.
-enganear

[dread]

When I first put in my mt-90 I didn't hear any additional noise but after 10k miles I am hearing a load whine squeak only at full lock low speeds. It doesn't happen every time but I was worried. This thread eases my concern.