Originally Posted By: dlundblad
Originally Posted By: MolaKule
More info is needed in this case.
I.e, What is the peak operating temperature of Ford's PTU?
For most lubes, any sustained temps above above 70% of the flash point is going to severely degrade the lube. So for this fully synthetic 75W140, any temp > about 280F is detrimental.
As others have stated, the Ford PTU design suffers from two main issues: 1) the low volume of fluid, 2) insufficient heat rejection.
Without an external cooler, short OCI's would be in order.
Could your comment be taken as 30% below the flash point too?
Easy math.. say the flash point is 100*F, you mean anything 70*F+ is detrimental?
Yes. Say FP is 400F.
0.30 X 400F = 120F. 400F - 120F = 280F.
0.7 X 400 = 280F, but with fewer keystrokes.
This only applies to a full synthetic gear lube.