Front/Rear Diff Oil Type and Fill Level

[nikhsub1]

Is using 75w-90 a problem since the diffs call for 75w-85?

 

[ALRaptor]

Is using 75w-90 a problem since the diffs call for 75w-85?

You will be good with 90. I think the 85 was for fuel economy standards.

 

[StraightSixM2C]

On the ford performance diff cover, The bottom fill plug is the one to use. It will require +1 qt over standard. The top fill plug is for weird pinion angles due to lifts or other weirdness.

 

[mpeychev]

Awesome replies!! Thank you so much everyone, I really appreciate it.

 

[Old-Raptor-guy]

On the ford performance diff cover, The bottom fill plug is the one to use. It will require +1 qt over standard. The top fill plug is for weird pinion angles due to lifts or other weirdness.

Ooooooor, you can use the top plug to fill until it comes out the bottom plug. Makes it a little easier.

 

[amREADY]

On the ford performance diff cover, The bottom fill plug is the one to use. It will require +1 qt over standard. The top fill plug is for weird pinion angles due to lifts or other weirdness.

Holding an extra qt seems like reason enough to swap out to one of these when I am due to change the fluid. I'm not sure how much weight to put on the fact they are 'stronger'. Seems like compared to thin stamped steel, it has to add some strength.
The ability to fill via top hole is nice.

 

[Nex]

The ability to fill via top hole is nice.

Always fill the hole...

 

[scpete24]

Always fill the hole...

All the holes

 

[New recaros]

Lube first, then fill

 

[StraightSixM2C]

If it’s tight and you can’t get it started, spit on it.