Mazda 6 Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
1,405 Posts
Discussion Starter #1
Taking my car into Soulspeed the 27th before heading down to Texas World Speedway for the road-course that week. In addition to adding 2 degrees of negative camber in the rear and the DE tech inspectiong, I'm having them swap transmission fluid with a Full Synthetic. I've been thinking Redline, but would like to get some input on this before I commit. What have others used and what's most recommended?

Also, do you need to swap out the center diff? My understanding is that it's really more of a PTO (Power take off) than a real diff, is that true?

Thanks in advance
 

·
Registered
Joined
·
34 Posts
Taking my car into Soulspeed the 27th before heading down to Texas World Speedway for the road-course that week. In addition to adding 2 degrees of negative camber in the rear and the DE tech inspectiong, I'm having them swap transmission fluid with a Full Synthetic. I've been thinking Redline, but would like to get some input on this before I commit. What have others used and what's most recommended?

Also, do you need to swap out the center diff? My understanding is that it's really more of a PTO (Power take off) than a real diff, is that true?

Thanks in advance
[/b]
Looks like different specs could be important b/c of the different types of metals used in the transmission. This is from a reliable guy on mazda3forums re: Royal Purple vs. Castrol:


.... "I am assuming that you are using Motul GEAR FF-LSD COMPETITION / SPORTS which is designated for use in passenger car transmissions/transaxles whereas some GL-5 gear oils are not because they may be corrosive to soft metals such as brass synchros.

For example:

http://www.castrol.com/castrol/productdetailmin.do?categoryId=82915494&contentId=6004023

"Exceeds API MT-1 lubricant for non-synchronized manual transmissions used in buses and heavy-duty trucks."

Nowhere do they indicate that their GL-5 synthetic gear oil is suitable for use in synchronized (passenger car) manual transmissions (that contain non-ferrous metal parts). I don't know for certain whether or not Castrol synthetic gear oil is bad for our transmissions but I would rather not take that chance. I would be more comfortable using a synthetic GL-5 that specifically states that it is non-corrosive to soft metals (which makes it compatible with Mazda's GL-4 requirement).

If we want to use a 75W90 gear oil that is:
1) fully synthetic
2) suitable for a transmission with synchros
3) suitable for a LSD
I'm not sure that there are so many good choices.

To add to the confusion, Red Line has 2 75W90 gear oils, one that is optimized for LSD's and one that is optimized for synchros."


I'll be changing mine in a couple of weeks, so I'll be interested to people's comments. At least with the MS6 you don't have to worry about oil being optimized for either LSD's or synchos.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #3
To add to the confusion, Red Line has 2 75W90 gear oils, one that is optimized for LSD's and one that is optimized for synchros."
[/i]

I'll be changing mine in a couple of weeks, so I'll be interested to people's comments. At least with the MS6 you don't have to worry about oil being optimized for either LSD's or synchos.
[/b]
So it looks like I'd need two oils then; one for the tranny and one for the rear diff. Honestly I was not planning on changing the oil in the rear end with a syn as this car is 90% of the time in FWD mode. Not sure if the cost would outweigh any gains you'd see at the track. I'm doubtful on that one, but will listen if someone has roadcourse experience that says different....

Heh, so I was looking at the Redline for the tranny to start, so looks like I'm back to where I started :)

Has no one changed out there tranny fluid with anything but redline?????????????????
 

·
Registered
Joined
·
1,484 Posts
Heh, so I was looking at the Redline for the tranny to start, so looks like I'm back to where I started :)

Has no one changed out there tranny fluid with anything but redline?????????????????
[/b]
I just switched my MS6's transmission to AMSOIL MTG. It's an API GL-4 oil, which is correct for the transmission. I've been happy with AMSOIL motor oils, so I expected good results-- but I'm actually disappointed. The shift quality is worse than with the OEM lubrication-- notchier, with slower synchronization. I suspect that the AMSOIL is too slipery for the sychromesh in this transmission.

People seem to have had good luck with Redline MT-90 on the regular Mazda6, so that's what I'm going to try next. Redline uses frictional additives in the MT-90 that are supposed to assist the sychromesh and help speed up the synchronization process.

I'll still recommend AMSOIL for motor oils and gear lubricants, but I wouldn't recommend their MTX lubricant for this synchronized application.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #5
I just switched my MS6's transmission to AMSOIL MTG. It's an API GL-4 oil, which is correct for the transmission. I've been happy with AMSOIL motor oils, so I expected good results-- but I'm actually disappointed. The shift quality is worse than with the OEM lubrication-- notchier, with slower synchronization. I suspect that the AMSOIL is too slipery for the sychromesh in this transmission.

People seem to have had good luck with Redline MT-90 on the regular Mazda6, so that's what I'm going to try next. Redline uses frictional additives in the MT-90 that are supposed to assist the sychromesh and help speed up the synchronization process.

I'll still recommend AMSOIL for motor oils and gear lubricants, but I wouldn't recommend their MTX lubricant for this synchronized application.
[/b]
Hmmm, this is why I wanted to ask before changing fluids. Last thing I want at the track is a HARDER to shift tranny. Do you know anyone who's used Redline? That's what's being recommended to me.

Thanks for the input
 

·
Registered
Joined
·
103 Posts
Don't know specifically for the speed, but I am going to be putting Royal Purple Maxgear in my 6s shortly. It, the redline MT90, and Specialty Formulations MTL-R where the only formulations I found meeting the specs that actually referenced use in manual transmissions and transaxles. This was important to me as many of the fluids out there appear to be designed more for heavy duty rear axles which has different demands from our application.
 

·
Registered
Joined
·
108 Posts
Don't know specifically for the speed, but I am going to be putting Royal Purple Maxgear in my 6s shortly. It, the redline MT90, and Specialty Formulations MTL-R where the only formulations I found meeting the specs that actually referenced use in manual transmissions and transaxles. This was important to me as many of the fluids out there appear to be designed more for heavy duty rear axles which has different demands from our application.
[/b]
Ive put in the RP maxgear in. I cant recommend it, factory fluid seemed better(may have to go back to dealer fluid or redline MT90). Seems more difficult to downshift into 1st from a slow roll even when doubleclutching. Happens in 2nd as well. :swearin:

Just bought some Castrol synthetic to try in the pto , see if that helps any.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #8
Ive put in the RP maxgear in. I cant recommend it, factory fluid seemed better(may have to go back to dealer fluid or redline MT90). Seems more difficult to downshift into 1st from a slow roll even when doubleclutching. Happens in 2nd as well. :swearin:

Just bought some Castrol synthetic to try in the pto , see if that helps any.
[/b]
So it sounds like the way NOT to go is the RP Maxgear as two of you have said the same thing; that shifts are harder and/or slower. Thanks for the input, just sorry you had to find out the hard way.

As to the Redline Tranny Fluid, I could have sworn I saw someone post something like 2 months ago on it, but I'm not finding the thread. Anyone have experience with it? If I don't get some word I may forgo changing the tranny fluid altogether. I'd hate to do it and end up having an experience like that with the RP Maxgear....
 

·
Registered
Joined
·
429 Posts

·
Registered
Joined
·
429 Posts
No problem, I'm going to order some soon myself.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #13
What’s your reasoning for adding camber to the rear? Doing that will just add more under steer.
[/b]
Heh, this is a funny story and shows what an idiot I can be. When I got my new wheels/tires put on a few weeks back it looked like there was WAY too much negative camber. So I had soulspeed crank it a bit more positive when I was doing a 4wheel hi-performance alignment. Got it back and drove it, now the back end feels light/loose on highspeed (80+mph) corners. It felt tighter/more hooked up with the old 215's and stock wheels! So I'm going to have them crank it back to stock, which was -1.5 degrees, I'm currently sitting at -.5 degrees.

Lesson I learned; don't believe your eyes :) The OEM wheels had the same -1.5 camber on them, the design of my new wheels simply made it appear MUCH more extreme than the OEMs.

I go in Monday morning at 11am for the camber fix, the MT-90 (which I just bough 3 qts of this afternoon) and oil change to 100% synthetic (Mobilone) before I hit TWS next weekend
 

·
Registered
Joined
·
1,484 Posts
For those who have been following this thread, I swapped out my AMSOIL for Redline MT-90 yesterday. The shift feel is much better-- the frictional additives in the Redline are definately helping the synchromesh do its job.

Since I didn't go direcly from the OEM fluid to the Redline, I can't make a really good comparison. From what I remember from the OEM shift feel, I think the Redline is a little nicer. The notchiness seems a little less, although I'm not sure the synchronization process happens any faster than with the OEM lubricant.

Overall, I'm pretty happy with the Redline MT-90.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #15
For those who have been following this thread, I swapped out my AMSOIL for Redline MT-90 yesterday. The shift feel is much better-- the frictional additives in the Redline are definately helping the synchromesh do its job.

Since I didn't go direcly from the OEM fluid to the Redline, I can't make a really good comparison. From what I remember from the OEM shift feel, I think the Redline is a little nicer. The notchiness seems a little less, although I'm not sure the synchronization process happens any faster than with the OEM lubricant.

Overall, I'm pretty happy with the Redline MT-90.
[/b]
Just got in from Soulspeed and I can tell you right off going from OEM tranny fluid to MT90 is a HUGE improvement. The shifts are smoother, faster and the gates are easier to find. For $9 bucks a bottle, it's worth the 3 bottles (2.6 quarts needed in our tranny).

Highly recommend it for anyone who wants to get a smoother shift :drive:
 

·
Registered
Joined
·
2,426 Posts
Just got in from Soulspeed and I can tell you right off going from OEM tranny fluid to MT90 is a HUGE improvement. The shifts are smoother, faster and the gates are easier to find. For $9 bucks a bottle, it's worth the 3 bottles (2.6 quarts needed in our tranny).

Highly recommend it for anyone who wants to get a smoother shift :drive:
[/b]
What entails draining the transmission fluid in our cars?
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #17
What entails draining the transmission fluid in our cars?
[/b]
I had Soulspeed do it as I'm not equiped at home to do it myself, i.e. floor jack, jack stands, fluid collection system, etc. They also did full synthetic in the transfer case, rear diff and changed the motor oil to Mobilone while I had it in for the camber fix.

I'm sure someone here will be able to tell you. That's what's great about this forum :)
 

·
Registered
Joined
·
1,484 Posts
What entails draining the transmission fluid in our cars?
[/b]
Not much different than changing the motor oil in a car's engine. This thread should be able to help you out with the drain and fill plug locations.

Make sure you can get the fill plug loose before draining the fluid. Leave the fill plug in (loosely) while draining, as the fluid will drain REALLY fast with the fill plug out and make a big mess.

I wasn't able to fit a socket and torque wrench on the drain plug (do to clearance with the frame), so you'll probably need to use an ordinary wrench to remove the plug. To properly torque the plug to spec, you'll need some sort of extension or crowfoot adapter for a torque wrench. If you can find a really short socket, you may be able to fit a torque wrench in the space without an extension.
 
1 - 18 of 18 Posts
Top