Cummins12V98 wrote:
JustLabs wrote:
STEVEO496 wrote:
lawnspecialties wrote:
Is there any reason why switching to 75W-140 would not be advised versus 75W-90?
I'm not wondering if its necessary. Just if its not advisable.
75W-140 will hurt your fuel economy. At higher temps (towing heavy) the 75W-140 will offer more protection though.
A higher viscosity gear oil isn't necessarily better. There is potential for the differential to run hotter and be lubricated less.
75/110 is the preferred viscosity when towing heavy. 75/140 is too heavy.
Seriously? I'm not sure I have ever even seen 75W-110. My Cherokee, Magnum, and Dak called for 75W-140 if towing.
FWIW, my Crown Vic calls for 75W-140 in police or livery service, 75W-90 otherwise.
