I have recently discovered Toyota manuals recommending "75W" GL-4 transmission oil. To my knowledge, 75W on the SAE J306 chart only shows the bottom end of the range, hitting 150,000 cP by -40ºC and having at least 4.1 cSt viscosity at 100ºC.
Based on that, I'm hearing people say they put 75W-90 or even 75W-140 in their transmissions and complain sharply about hard shifting with either. Some Toyota dealers are even putting in 75W-90 and causing hard shifts.
After a lot of searching, I found somewhere that the "Genuine" Toyota fluid is 75W-85, but at least one dealer insists that it is 75W-80. On line I found one brand who now lists a 75W and says it is their renamed 75W-85.
Nissan is much more specific, requiring 75W-80 in some transmissions and 75W-85 in others.
So two questions:
--Am I right in understanding that the 75W is only half of the spec? and
--Why would Toyota be so vague about the spec? They must know there are people who need to change the fluid where "Genuine" Fluid is not available.
And finally, since the SAJ306 table allows huge differences, has anyone had their genuine fluid analyzed?
Based on that, I'm hearing people say they put 75W-90 or even 75W-140 in their transmissions and complain sharply about hard shifting with either. Some Toyota dealers are even putting in 75W-90 and causing hard shifts.
After a lot of searching, I found somewhere that the "Genuine" Toyota fluid is 75W-85, but at least one dealer insists that it is 75W-80. On line I found one brand who now lists a 75W and says it is their renamed 75W-85.
Nissan is much more specific, requiring 75W-80 in some transmissions and 75W-85 in others.
So two questions:
--Am I right in understanding that the 75W is only half of the spec? and
--Why would Toyota be so vague about the spec? They must know there are people who need to change the fluid where "Genuine" Fluid is not available.
And finally, since the SAJ306 table allows huge differences, has anyone had their genuine fluid analyzed?