Question Rear Dif

[sdcham1]

Guys i just checked my rear dif is leaking, I have a 2004 250 superduty with a 6.0, My question is can I use synthetic fluid?

 

[DaveBen]

Yes, it came with syn gear oil from the factory.

Dave

 

[JLDickmon]

no RTV with synthetic fluid.. you must use a gasket

 

[WD40]

I may be wrong but I was thinking that on my 06 with 4.10 gears the stock cover had a
gasket built into it. My truck came with synthetic fluid?
Doug

 

[BIG DUTY]

Yes use sythetic. Both my front and rear have synthetic and are sealed with black RTV. They use a silicone gasket maker right from the factory. As far as I know, mine did not have a paper gasket.

 

[JimmyDee]

no RTV with synthetic fluid.. you must use a gasket

I just changed my fluid and there is a tag on one of the cover bolts that says, use 75-140 synthetic only. Is had a black RTV gasket and I reinstalled the cover with black RTV. Go ahead and used the RTV, its what Ford used when they manufactured it.
Jim