Again, from a patent (I know, I should get a life):
Nippon patent for fuel efficient ATF
I don't know who makes Toyota's WS, but I know it isn't Nippon.
Interesting tidbits [and my comments]:
"There are recently proposed automatic transmission fluids having a lowered viscosity, for example, in JP-2004-169025-A, JP-2004-155924-A, and JP-2004-155873-A . These lubricants have excellent sustainability of anti-shudder property, low-temperature viscosity characteristics, and oxidation stability, but are yet to be improved in excellence and balance of durability of friction characteristics, contribution to energy conservation, and anti-fatigue performance on gears."
[are these patents connected with WS?]
"the lowered viscosity of lubricants used in these parts may remarkably shorten their fatigue life, causing seizure or the like to result in troubles in the transmission. In particular, when a phosphorus extreme pressure agent is used for improving extreme pressure property of a low-viscosity lubricant, fatigue life of gears is remarkably impaired, so that it is usually hard to lower the viscosity of such lubricant. On the other hand, a sulfur extreme pressure agent may improve fatigue life of gears, but impairs oxidation stability, so that a large amount of antioxidants is required."
[Well, WS does contain low P. Redline with higher P doesn't go lower than 6 cst].
"If the kinematic viscosity at 100 °C of the present composition is higher than 5.8 mm 2 /s, the energy-conserving performance given by reduction of agitation resistance and excellent low-temperature viscosity characteristics cannot be achieved sufficiently. If the kinematic viscosity is lower than 5.6 mm 2 /s, fatigue life of gears cannot be prolonged sufficiently."
[as everyone knows, most ATFs shears down under 5.5 if given enough time (15-30000 miles). WS starts at mid 5 and shears to high 4 in 60000 miles].
Nippon patent for fuel efficient ATF
I don't know who makes Toyota's WS, but I know it isn't Nippon.
Interesting tidbits [and my comments]:
"There are recently proposed automatic transmission fluids having a lowered viscosity, for example, in JP-2004-169025-A, JP-2004-155924-A, and JP-2004-155873-A . These lubricants have excellent sustainability of anti-shudder property, low-temperature viscosity characteristics, and oxidation stability, but are yet to be improved in excellence and balance of durability of friction characteristics, contribution to energy conservation, and anti-fatigue performance on gears."
[are these patents connected with WS?]
"the lowered viscosity of lubricants used in these parts may remarkably shorten their fatigue life, causing seizure or the like to result in troubles in the transmission. In particular, when a phosphorus extreme pressure agent is used for improving extreme pressure property of a low-viscosity lubricant, fatigue life of gears is remarkably impaired, so that it is usually hard to lower the viscosity of such lubricant. On the other hand, a sulfur extreme pressure agent may improve fatigue life of gears, but impairs oxidation stability, so that a large amount of antioxidants is required."
[Well, WS does contain low P. Redline with higher P doesn't go lower than 6 cst].
"If the kinematic viscosity at 100 °C of the present composition is higher than 5.8 mm 2 /s, the energy-conserving performance given by reduction of agitation resistance and excellent low-temperature viscosity characteristics cannot be achieved sufficiently. If the kinematic viscosity is lower than 5.6 mm 2 /s, fatigue life of gears cannot be prolonged sufficiently."
[as everyone knows, most ATFs shears down under 5.5 if given enough time (15-30000 miles). WS starts at mid 5 and shears to high 4 in 60000 miles].
