Alternative oil (redline)

[Outbackman]

I need to change the oils in the driveline. Has anyone put in redine oils? I use them in my miata and shifting is a little smoother.

 

Will the dealer put in the oil of my choice even if I have to supply the oil?

 

Thanks

[edrach]

I use the 75W-90NS redline gear oil in my '91 Legacy which had a 3rd gear crunch when I bought it 60K miles ago. Gearbox is smooth now; I've either gotten used to avoiding the crunch or the redline is doing it for me.

I need to change the oils in the driveline. Has anyone put in redine oils? I use them in my miata and shifting is a little smoother.

 

Will the dealer put in the oil of my choice even if I have to supply the oil?

 

Thanks

[powderhound]

I have redline NS in the gearbox...also to attempt to cure failing synchros...worked well for about six months now same old same old...crrrunch. I have mobil 1 in the rear diff.

[f15xxx]

try MT-90. the 75-90 and NS are way to slippery to allow syncros to properly slow down. it's a shame to see this issue come up time after time. once and for all, the MT-90 is the way to go.

[Setright]

Well, I used to trumpet "Castrol TAF-X" also known as "Syntorq" but I have discovered that Valvoline Synpower 75W-90 is just that little bit better, and probably easier/cheaper to get a hold of in the States.

 

Both are far better than Redline. Zero crunching with Valvoline.

[blitz]

try MT-90. the 75-90 and NS are way to slippery to allow syncros to properly slow down. it's a shame to see this issue come up time after time. once and for all, the MT-90 is the way to go.

As far as I know, 75W-90NS & MT-90 are both "high friction" (non friction modified) 75W-90 lubes. The only difference between them that I can find on the Redline website is the presence of sulfurous high-pressure hypoid additive in the NS. This is good for the diff gears, but corrosive to the synchro metal in the trans ...take yer pick.

 

**** ******!

[dmanaenk]

As far as I know, 75W-90NS & MT-90 are both "high friction" (non friction modified) 75W-90 lubes. The only difference between them that I can find on the Redline website is the presence of sulfurous high-pressure hypoid additive in the NS. This is good for the diff gears, but corrosive to the synchro metal in the trans ...take yer pick.

 

**** ******!

Isn't NS a 75w90 without sulfurous high-pressure hypoid additive, is it?

[blitz]

Isn't NS a 75w90 without sulfurous high-pressure hypoid additive, is it?

NS = Non-Slip. It's the same as the regular 75W-90 except it's not friction modified. This info is from the Redline website.

 

**** ******!

[bulwnkl]

...the presence of sulfurous high-pressure hypoid additive in the NS. This is good for the diff gears, but corrosive to the synchro metal in the trans...

 

Although I agree that the MT-90 and the NS are both "high-friction," the presence of a sulfur-phosphorous EP additive in gear oil does not automatically mean it's corrosive to the synchros; that's an old wives tale. Sulfur compounds can become reactive under certain circumstances (i.e. sump temperatures above ~250-275 F depending upon the formulation), and sulfur in certain old-style, low-grade base oils will become corrosive quickly. However, most (all?) gear oils sold in the USA & Canada have metal deactivators to address the issue at normal operating temperatures, and therefore are not corrosive. Thus, one need not choose between synchro corrosion and shiftability in a properly formulated, quality lubricant like Redline or those from Specialty Formulations.

 

Also, to each his own, but these Subies specify a GL-5 lube in the mtx, so MT-90 does not meet the spec. I know many guys run a GL-4 or GL-4 mix, but nobody seems willing to confess to running a GL-4 for any considerable mileage to see what happens to the diff.

[f15xxx]

the fact that mt-90 is a gl-4 doesn't matter a FF to me. i go by what works for the application. i have tried all the common synths in the 5mt and the mt-90 has the lowest gear clash. when you guys stop worrying about the label and use a lube that solves the problem, you will be set free. btw, i used mtl (a lighter grade of mt-90) for 210,000 mi in a 95 corolla transaxle over a 10 year period (even though the label called for a 75w-90) without any dire effect. to each, their own. go out and test everything out there, i know you'll eventually come home to mt-90.

[blitz]

Well damn, if I admit to running a 50/50 blend of MT-90 & 75W-90NS does that qualify me as a brilliant strategist, a spineless fence-rider, or just a ******* *******?

[f15xxx]

if that combo works for you, i would have to say that you are a brilliant rugged individualist. i used to blend fork oil in a 90 katana 1100. honestly, manually trannys are somewhat finicky, i used mtl in a 90 zr-1 without any ill problems. these sube trannys seem very prone to gear clash and the mt-90 was the only stuff that cleared it up. mobil-1 and the other redline products did NOT solve the problem. tranny has 80k mi on it and i suspect PO did a lot of highway driving. clutch seems to be ok with slight judder only when extremely cold. we just changed out 92 ranger plow truck to mt-90 and it seems to have helped with worn 1-2 syncro. YMMV, of course.