Diff Fluid?

[Zeusmotorworks]

Don’t believe that is true... at least every built/regeared diff I’ve every paid for came with the warning not to over fill.

 

[Dustan]

Over filling the diff is also a great way to test your axel seals!!!!

 

[Badgertits]

Over filling the diff is also a great way to test your axel seals!!!!

it’s not overfilled if it’s filled to the 2nd hole it’s there for a reason - for guys driving the rap like meant to be

 

[Zeusmotorworks]

Everyones understanding was it is there for lifted vehicles (higher pinion angle). Tilting the diff effectively changes the shape of the fluid reservoir.

Pretty sure we’d ALL like to see where anyone found where it was added “...for guys driving the rap like meant to be” however amusing that sounds.

After close to 40 years turning wrenches and just plain feeling old, I have ZERO interest in being “right”. We should however have the incessant need to find accurate information.

 

[George Dyck]

Too much won’t hurt that’s why they have burp valves


Too little? That’s another story

Actually, too much can hurt. It can cause foaming and lead to overheating. The “burp valve “ is to allow air, which expands a lot when heated, to escape. Without it, the diff would pressure up when it gets warm and potentially push oil out of the pinion or axle seals.

 

[KAH 24]

If you don’t mind sharing, which diff cover? I’m looking at various options and watched a Gale Banks video on diff covers—which for nerds like me was interesting.

 

[nikhsub1]

If you don’t mind sharing, which diff cover? I’m looking at various options and watched a Gale Banks video on diff covers—which for nerds like me was interesting.

https://www.cjponyparts.com/ford-pe...ntial-cover-9-75-f-150-2009-2020/p/M4033F975/

 

[sixshooter_45]

Anyone ever make a purchase from Vivid Racing?

They have them for $203.xx

 

[JL Gordon]

Reading the description of the cover, it talks about lowering your rear not lifting. This is a Ford performance part which are usually geared towards street/track racing. This diff has been in almost every ford produced, and the raptor is a fairly new dor Ford to get into off road racing.

Makes me wonder if top hole is correct and lower hole is for lowered vehicles. ‍

What you should do is measure how much fluid comes out of your factory diff, and then put that much back in and see what level that fills to.

Also...you could just read the manual which says 5.5 quarts of 75w-140 (2013, but all the same I believe).

 

[nikhsub1]

Reading the description of the cover, it talks about lowering your rear not lifting. This is a Ford performance part which are usually geared towards street/track racing. This diff has been in almost every ford produced, and the raptor is a fairly new dor Ford to get into off road racing.

Makes me wonder if top hole is correct and lower hole is for lowered vehicles. ‍

What you should do is measure how much fluid comes out of your factory diff, and then put that much back in and see what level that fills to.

Also...you could just read the manual which says 5.5 quarts of 75w-140 (2013, but all the same I believe).

Uh, the Gen 2 uses 2.7 quarts in the rear diff - 75w85 is specified. The FP cover does not increase the size of the diff so only add back just under 3 quarts.