For those that have LSD noise after switching to MT90

[)EIB(]

Thought I should share this here just for reference. Below is the official response I got from Redline in regards to LSD noise after switching to MT90 and adding Friction Modifier to reduce the noise:

------------------------------------------------------------------------
Below are the results from the Red Line Oil web site Application Request Form.

It was placed on 12/11/2008 10:25:47 PM.

Application Request Form Information
-----------------------------------------------
Name : --------
Email Address : -----------------
Address : ------------------
Address 2:
City : --------
State : ---
Zip : -------
Make : Mazda
Model : Mazdaspeed3
Year : 2007
Engine Type : 4 cylinder turbo direct injected
Differential Size/Type : Torsen Cone Type Super LSD
Transmission Type: 6-speed transaxle
Issues : I've recently replaced the transmission fluid with MT90 which is recommended for my vehicle. However, I'm experiencing LSD noise under low gear low speed tight turning in cold operating temperature. The transmission is shifting perfectly smooth under all condition. The only problem I have is the LSD noise after switching to MT90. I understanding your company makes a friction modifier that can be used with the MT90. What are the effects of adding friction modifiers to the MT90? Will it eliminate the LSD noise at the expense of shifting quality? If I choose to add the friction modifier, what ratio of mixture is appropriate for my application? If I choose NOT to add the friction modifier, will the LSD be damaged or its longevity shortened due to the noise? What is your recommendation in regards to whether or not to add the friction modifier?


)EIB(,

Thank you for contacting Red Line Oil, the cone type limited slip units are generally not particularly prone to chatter. The Friction Modifier can be added to the MT-90 though too much will be detrimental to the shiftability. If you wanted to add some I wouldn't exceed about 1% by volume, less than an ounce. The chatter is more of an annoyance than being harmful, I wouldn't expect it to affect the life. If the noise isn't annoying, then I would just live with it, if too annoying then I would increase the slipperiness of the fluid slightly, you could decide that.

Regards, Dave
Red Line Oil
-------------------------------------------------------------------------

After receiving this response, I decided not to add the friction modifier and just live with the noise.

 

[Abilor]

Good to know. I'd wear earplugs too.

 

[amascio]

I notice you mention cold weather. In warmer weather does the noise stop?

 

[AGspeed3]

I've had MT-90 in for 15k miles or so. Same issue - cold mornings until the engine warms up I get the same thing. Wasn't as bad when the fluid was new, but has gotten worse over time. Noise stinks, but the shifting when cold is still better than stock fluid.

 

[)EIB(]

amascio: for the most part, the noise happens only in cold operating conditions. Once the transmission warms up, the noise either goes away or barely noticeable with the steering wheel at full lock moving at very low speed (like driving in a parking structure, for example)

AGspeed3: I've had the fluid for a few thousand miles and I noticed the noise has gotten slightly worse as well. But like you said, the shifting quality is just so much better than the stock fluid under all condition that I would rather live with the noise than switching back....

 

[dan7225]

i've been using mt90 for a few years in my cars.
honestly ever since i've put it in the ms3, 2nd gear grinds a lot (revving & double clutching shouldn't be the answer to daily driving)
i have added about 5 ounces of frinction modifier (oreilly auto parts brand), and no change with the noise.
people have always seemed to rave about MT90 gear oil. i've probably spent over $250 on it in my last 2 cars. i dont think it works that great. i always seem to have some kind of gear grinding problem with it.
one thing i've noticed is that once you use it, going back to regular gear oil is a mistake. the shifting really sucks after the switch back to regular. sounds like a contradiction right? i just know the oil that came stock in both cars seemed to shift all gears just fine. no whine no grind. if i switch back to regular oil in the ms3 i expect it will probably be worse than with MT90.
i'm honestly thinking about going with redline heavy duty shockproof oil.
i've heard people rave about it after it warms up. maybe atleast then i wont be grinding gears.

 

[amascio]

If you have the $$$ here's what I am using with great results...Ford part # XT-M5-QS.

I was running Redline MTL to get better shifts and it WAS better, but kinda out of spec (70W80). After sifting the web on the XT-M5-QS and finding out that it was doing well, I tried it.

It is great! Shifting at any temp is excellent with the 1-2 gear grind a thing of the past. My trannie is virtually silent now which is assuring. It has been in my box for 8k miles so the stuff is no flash in the pan.

Google XT-M5-QS and look for the Ford Chemicals web page and read about it.

It was developed in Germany for some difficult shifting Getrag FWD boxes that Ford had in production.

I paid $19.25 a quart but I have seen it on the web for as low as $15 a quart.

For a 75w90 GL4 weight oil it seems thin but it is recommended by Ford for all their manual boxes that require 75w90 GL4. Ford Chemical has other oils in the 75w90 range but the XT-M5-QS is their TOP oil.

It is so well engineered that Ford considers it suitable for lifetime fill.

It doesn't seem to be wearing out so it's going to stay in for quite some time......

Cheers all!

 

[amascio]

An addition to my post...

It doesn't get really cold here in the Houston area so stating that the XT-M5-QT works great in all temps, in my case, might be a stretch - Houston's winter temps rarely go below 40F.

However, today it was uncharacteristically cold here, 30F, so I made sure to make the car do some sharp, low speed turns right after firing her off - no LSD noise whatsoever. I put the car in my cul-de-sac and made it drive slow in both directions at full cock and the lube is keeping things quiet.

Now at -20F I couldn't say whether the stuff would make noise or not, I do know that it's good to go just below freezing.

And at 30F, the shifting was fine - any manual trans in cool weather will have some notchiness to it and my car is no exception, but it no longer grinds the 1-2 shift ever and the cold notchiness is gone in less than a minute.

I attribute the success of this product to it's exellent base oil and exotic add pack - German lubrication engineers rarely underdo anything.

Cheers all!

.

 

[tru-boost]

My trans has had mt90 for anout 20k now. It doesnt make noise nut the shifts are tough for a few minutes in cold temps. DO NOT USE ANY FRICTION MODIFIER im this transaxle. It will ultimately kill your synchros and in all honesty this diff type works best without it. Just dont do it!

 

[07speed3]

im running royal purple and i get that noise also, i dont think that it had friction modifier.

 

[tru-boost]

Rp has modifier in it from the get go. Its no good for this tranny.

 

[amascio]

Have we ever figured out just exactly who makes the transmissions for these cars?

If we could get that nailed down, we could *uck off Mazda and contact the trans manufacturer and let them tell us what the deal is.

Does anybody know who makes them.....

 

[tru-boost]

It doesnt matter who makes it, what matters is whats in it. It has a conical type limited slip and triple con synchros for gears 1-3 and double cone for the rest. That means the diff needs no friction modifier and if added it will over te destroy your synchros.

 

[amascio]

At one point in time it was thought to be this transmission:http://www.getrag.de/en/250 Who really knows...

 

[08_MS3_GT]

i've got the same noise issues - with Amsoil MTG transmission fluid. it doesn't seem to go away when warm. i have 3qt of MT-90 on-hand and was considering swapping it in.

is this sort of noise "normal"??? i mean, i wouldn't expect high-grade GL-4 synthetic oil to damage an LSD. i can easily put up with the noise if i'm fairly certain that it's not indicative of a part failure.

i swapped winter tires on @ the same time i swapped in the fluid, so i've thought that the tires were to blame. i guess the noise has been there the whole time, and, if MT-90 is causing it as well, there's no reason for me to switch?

 

[)EIB(]

After some mileage with the MT-90, I've noticed that the noise is there even when the gear box is warmed up. But the noise is less intense then when it is cold.

According to the response from Redline, the noise is more of an annoyance than harmful. So if it's really a concern, you might want to trying putting in a very small amount of friction modifier to see if that would eliminate the noise. Amsoil also makes a friction modifier for use with their gear lubes to reduce LSD noise, which is called Amsoil Slip Lock. Give that a try and see how it goes.

I wouldn't switch to MT90 in your case since you already have Amsoil MTG which is a good tranny lube and based on my experience the MT90 would result in the same noise.

 

[1speed3]

oils

I work for Johnson Subaru and by trying every oil / diff fluid in the world i will tell you there is nothing better then Amsoil. I have had royal purple, greddy fluid, redline fluid, mobile one, Valvoline race oil, and many more. I will tell you for performance and longevity Amsoil is the best by far. It is the best for the money hands down. I had this same sound on cold mornings and it drove me nuts. It happened with royal purple and redline for me.

SWITCH TO AMSOIL ! Best thing you could ever do for yourself.

 

[Fat_Dave]

has anyone tried pennzoil syncromesh? i have it in my trans in my zx2 and it shifts like butter

 

[pjb1180]

Move south

 

[john blutarski]

I'd like to add that the same thing happened in my WRX. As soon as I switched from the factory fluid fill to Redline, I got much more gear whine. It never went away after that no matter what fluids I tried and I tried several even a refill of the stock stuff. The good news is it still shifted and drove perfect for 20k miles till I traded in the car.