I am finally getting ready to change my diff fluid in my f150.
I grabbed some supertech 75w-90 after taking a look at the sds it's a group 3 base stock blended by Warren and looks fairly equivalent to Mag 1 going by flashpoint which are identical and viscosity which is similar.
Since the book specs 75w-85 on the main capacity page. I wanted to take a look at the severe service page way in the back.
So I found this blurb that appears to allow 75w-140 in situations where someone is actually using the truck as a truck.
In my opinion it looks like you can run 75w-85 up to 75w-140 according to Ford. It looks like you can skip buying the expensive 75w-85 from motorcraft unless you operate in Artic conditions or want that .1 mpg increase.
Normal Vehicle Axle Maintenance
Rear axles and power take-off units with
synthetic fluid and light-duty trucks
equipped with Ford-design axles are
lubricated for life; do not check or change
fluid unless a leak is suspected, service is
required or the assembly has been
submerged in water. During long periods
of trailer towing with outside temperatures
above 70°F (21°C) and at wide-open
throttle for long periods above 45 mph
(72 km/h), change non-synthetic rear axle
fluid every 3,000 mi (4,800 km) or three
months, whichever comes first. This
interval can be waived if the axle is filled
with 75W140 synthetic gear fluid meeting
Ford specification WSL-M2C192-A, part
number F1TZ-19580-B, or equivalent. Add
friction modifier XL-3 (EST-M2C118-A) or
equivalent for complete refill of
Traction-Lok rear axles.
I grabbed some supertech 75w-90 after taking a look at the sds it's a group 3 base stock blended by Warren and looks fairly equivalent to Mag 1 going by flashpoint which are identical and viscosity which is similar.
Since the book specs 75w-85 on the main capacity page. I wanted to take a look at the severe service page way in the back.
So I found this blurb that appears to allow 75w-140 in situations where someone is actually using the truck as a truck.
In my opinion it looks like you can run 75w-85 up to 75w-140 according to Ford. It looks like you can skip buying the expensive 75w-85 from motorcraft unless you operate in Artic conditions or want that .1 mpg increase.
Normal Vehicle Axle Maintenance
Rear axles and power take-off units with
synthetic fluid and light-duty trucks
equipped with Ford-design axles are
lubricated for life; do not check or change
fluid unless a leak is suspected, service is
required or the assembly has been
submerged in water. During long periods
of trailer towing with outside temperatures
above 70°F (21°C) and at wide-open
throttle for long periods above 45 mph
(72 km/h), change non-synthetic rear axle
fluid every 3,000 mi (4,800 km) or three
months, whichever comes first. This
interval can be waived if the axle is filled
with 75W140 synthetic gear fluid meeting
Ford specification WSL-M2C192-A, part
number F1TZ-19580-B, or equivalent. Add
friction modifier XL-3 (EST-M2C118-A) or
equivalent for complete refill of
Traction-Lok rear axles.