Thanks, I used the the black RTV sealer, I also used an actual gasket as well.

My problem is I also have a leak on my pinion seal, once that is done this weekend i should be ok as far as leaks go.

 

Yes.

 

Well, i fixed the pinion leak about 3 weeks and it stopped that leak. I am now leaking again from the diff cover, and i used RTV black sealant as well as a gasket. Why would it be leaking?

Cover is fine and not cracked. I put a thin bead of sealant around the diff on the truck and a thin bead on the diff cover it self. Then i placed the gasket on the diff cover and bolted in on.

Funny thing is its not leaking from the bottom but the left side ( around 9 o'clock)

Any idea's?

 

Check the cover bolts for uneven torque. Also, is the fill plug tight? The fill plug is around the 9 o'clock area. If it is leaking, it could be drifting to the cover area.
Or, a piece of the old gasket could still be on the cover causing a gasket failure.

 

I used a torque wrench on the cover bolts, i torqued them to 35 foot pounds. I checked the fill plug and its dry in that area with no traces of oil leaking to the cover. When i took the cover off a month ago It was cleaned 100% with no old residue or gaskets left behind.

That's why im confused with the leak. I doubled up with RTV black sealant, as well as a gasket for an extra seal.

 

Ttt

 

That is a little puzzling. Since I am not a professional, I really don't know where else to go with this. However, the next thing I would look at as a weekend mechanic is the cover its self in terms of it being bent or otherwise damaged in some way. If the bolts are all tight and the gasket is in place, there must be a failure where the two surfaces meet.

 

I have no choice but to take the cover off again today, already purchased another gasket, drain my oil and refill again. The Oil here 75-140 is $19.99
X3 bottles that i need. Friction modifier $5.00 , and gasket is $10.00 = $75.00

This will be my second go at it in 1 month $150.00 rear diff oil change. that sucks

 

Sorry to hear that. If it were me, I would use a very thin layer of rtv, just enough to hold the gasket in place. I don't know who else may do this, but I add a touch of rtv to the top end of the bolt so it will seal as it is tightened. Not on the actual threads.

If there is a vent tube, make sure it is not plugged up.

Good Luck.

 

I would either use either the gasket or RTV but not both. Male sure the vent and tube are not plugged.

.

 

I had used a gasket and RTV together, figured with both, it would never leak again. I had applied RTV on the diff housing and RTV on the cover, with my gasket in between.

I didnt even know there was a vent tube. Where is it located, should i blow compressed air through the tube?

 

I am glad a tech stepped in. I wish you good luck with your issue and hope this time everything works out. You have some time to get the right direction from the right people, as I don't think it is leaking so bad that it will run dry anytime soon.

 

Pauly, do you happen to know where the vent tube is located?

 

Post #18 in this link:https://www.f150online.com/forums/ar...ts-pics-2.html

Shows a picture of the vent. Hope this helps.

 

I just had a look on my truck and I see the similar area where the vent tube should be , but on mine the tube continues on towards the front of the truck, I thought there would be an opened end.