Very productive day. A buddy of mine (who's dad owns a Ford dealership) took over the shop for the day. Got my truck up on a lift to do a tire rotation, serious check on the breaks/rotors, and do a full drain and fill on the transfer case and both diffs.
Mechanics don't work on Sat. Just the head mechanic that is there for parts support. Did all the work myself with a helping hand and info from my buddy. He knows more about this than I do. Then for the really important checking of stuff I got the head mechanic to come take a look once everything was apart.

Truck only has 62k on the clock so I didn't think they would be that bad.

Transfer case fluid was pretty dark but still red in color so I'm guessing it was alright.
Rear Diff was likewise kinda dark and the mechanic said it definitely was time to change it.

Front Diff is where I really kinda got suprised.
Once the cover was pulled the fluid was milky. I knew from working around lower units on boats that it meant water in the fluid. I can't figgure how water would have gotten in there. I do a little off roading in water, but rarely over a foot or so deep at it's worst and not rarely that deep. It has "never" sat in water deep enough to submurge the diff.
Now once the cover was all the way off I did notice that the factory applied sealant on the front couldn't have been applied worse. It was very very thin and nearly non existant in places. The rear didn't look that way at all.
Spent a good amount of time cleaning all the milky looking stuff out of the diff before sealing it up with the motorcraft specialty stuff that the mechanic told me was better than what is normally used.

Everything was refilled with the suggested motorcraft fluids.

Everything is all buttoned up and no leaks

Spent a great deal of time checking and double checking everything under there that I could while I had free reign of having it up on a lift. All boots are perfectly fine. Not a single crack let alone a hole.

Where else could the water have come from? I'm stumped.



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You need to check on how low the breather tube is sitting and if where it is located whether splashed water could get into the tube.

 

What kind of sealant did you use on the differential covers and did you have to let it set before you added the fluid. Is it ok to drive after the fluid is added or does the sealant need time to cure first? I'm getting ready to do mine... hopefully this weekend if the weather is good.

 

I don't remember exactly what the sealant said except that it was motorcraft. It was in a fairly large tube as far as gasket material goes. The Ford tech said it was the same stuff that is used by the factory and that what the book says to use isn't the same stuff. I let it sit for 15 mins or so before adding fluid just for safety sake but the tech said it wasn't needed. I was told and did use a break cleaner on the inside to get it really clean and went through great pains to get every scrap of the old sealant off of both diff and cover.

The tech also said that the fluid and/or friction modifier that is recomended by Ford now had been changed from what was listed on the tabs that are bolted to the diffs. So I'd check that out. I don't remember the differences. He's been thier top mechanic for 25 years so what he told me to put in, when in. LOL He had some neat short cuts and tips that I would have never thought of.

I would have never thought to use a break cleaner to clean it out really well. However you do have to use rags and compressed air to get out anything that doesn't dry. You don't want that cleaner mixed with the lube.

 

I just changed the front diff oil in my 2004 and it was exactly how you described, (white and milky) From what i could tell the whit stuff was an assembly grease or grease used to set up the ring and pinion at the factory. Let me know what you think. My truck was never in deep water either.
check this out too. http://www.fordf150.net/forums/viewtopic.php?t=63186

- John

 

your just a regular mechanic now arent ya? Could you work on my toyota too?


See ya at spooktackular im the pirate