Amsoil 75W-85 EP Gear Lube and ULV ATF

[MolaKule]

My Subaru BRZ manual suggested using a 75w90 fluid was okay in place of 75w85, but noted that it might cause more noise. Do you know any way a 75w85 might be less noisy than 75w90 ? , what causes the noise ? I have 75w90 in my BRZ now and it is quiet so far.

Your question was answered here:

Post in thread 'Can Differential Fluid Viscosity Affect Torsen LSD Engagement ?'

Mar 23, 2025

That is good news, thanks for the reply, then one should be able to run any viscosity that is within reason and not affect operation of the LSD for Torsen units. I think our owner manuals are a bit incorrect as they talk about potential extra noise and vibrations when going from 75w85 to 75w90, I think they are plain wrong on that.

In a real Torsen, there is no engagement or disengagement of anything. Torsen basically means torque sensing via the gearing. The extra gearing is always in mesh.

• MolaKule

 

[zeroptzero]

Your question was answered here:

Post in thread 'Can Differential Fluid Viscosity Affect Torsen LSD Engagement ?'

Mar 23, 2025

That is good news, thanks for the reply, then one should be able to run any viscosity that is within reason and not affect operation of the LSD for Torsen units. I think our owner manuals are a bit incorrect as they talk about potential extra noise and vibrations when going from 75w85 to 75w90, I think they are plain wrong on that.

In a real Torsen, there is no engagement or disengagement of anything. Torsen basically means torque sensing via the gearing. The extra gearing is always in mesh.

• MolaKule

Thank you for the reply and link to the other thread. It is unfortunate that some owner manual statements can be misleading for owners and you have little to refer to other than that. We try to apply common sense to issues like that, and hope for the best.

 

[SubieRubyRoo]

i guess my point is, 75w90 and w85 are not that different,

amsoil spec 75w90 and 110 for my lx570, but the new toyota specs the w85

i suppose it is good for those who just want precisely that weight

i wonder if it is more shear stable than 90wt?

Read my 75w90 thread. There are several of those that shear less than 2%. I highly doubt there’s any 75w85s more robust than that, and not like it’s going to make a difference.

 

[martinq]

Why is it only a 75W instead of 70W? I would think going down to SAE 80 or 85 would also give room to improve cold flow.

 

[SubieRubyRoo]

Why is it only a 75W instead of 70W? I would think going down to SAE 80 or 85 would also give room to improve cold flow.

Why bother? Amsoil & Redline 75w90s have pour points in the -45*C range, and Motul Gear 300 & HPL Gear Life CC have pour points in the low -60s* C… Even the plebeian Mobil 1 75w90 has a pour point of -39*C. In other words, available gear oils have pour points as good as any 0wXX oil has, so what’s the need for anything lower than that? The gear oils’ cold temperature performance is not going to be the limiting factor in vehicle operation.

 

[ford250]

Why bother? Amsoil & Redline 75w90s have pour points in the -45*C range, and Motul Gear 300 & HPL Gear Life CC have pour points in the low -60s* C… Even the plebeian Mobil 1 75w90 has a pour point of -39*C. In other words, available gear oils have pour points as good as any 0wXX oil has, so what’s the need for anything lower than that? The gear oils’ cold temperature performance is not going to be the limiting factor in vehicle operation.

Some just don’t get it

 

[martinq]

Some just don’t get it

I just question the quality /performanceof a "synthetic" gear oil that's below SAE 90 and can't pass for 70w. Aside from fuel efficiency, why go below SAE 90 if it's not for better extreme cold performance?

 

[Bullwinkle007]

Perhaps Amsoil's customer base has changed and the demand for a 75W85 is finally high enough?

What’s wrong with sticking to the Iong time industry standard 75/90

 

[The Critic]

What’s wrong with sticking to the Iong time industry standard 75/90

Actually, industry standard has been 75W85 on lighter duty vehicles for quite some time....probably almost a decade.
There is actually a decent difference in viscosity between 75W85 and 75W90.

 

[Bullwinkle007]

Actually, industry standard has been 75W85 on lighter duty vehicles for quite some time....probably almost a decade.
There is actually a decent difference in viscosity between 75W85 and 75W90.

75/90 75/85. Not much difference. No noticeable mpg that you could register. It’s not like drag racing where a thousands of a second can make break a race

 

[zeroptzero]

75/90 75/85. Not much difference. No noticeable mpg that you could register. It’s not like drag racing where a thousands of a second can make break a race

I sided with 75w90 for a bit more viscosity protection, over 75w85