Diff Fluid change
Tuned
Joined: Jul 2009
Posts: 489
Likes: 4
While all you 'diff' guys are out there: just bought and 05 auto 4x4 with 55K.
Should I change out my 2 diffs and transfer case because I have know idea what this truck has been put through?
It doesn't look like anything has been changed to date (very dirty and rusty).
Did the tranny & all filters but hesitating on overkill on the rest.
I've owned trucks that were 20 years old with all original diff fluids so is it really a worry on a 5 year old truck?
Should I change out my 2 diffs and transfer case because I have know idea what this truck has been put through?
It doesn't look like anything has been changed to date (very dirty and rusty).
Did the tranny & all filters but hesitating on overkill on the rest.
I've owned trucks that were 20 years old with all original diff fluids so is it really a worry on a 5 year old truck?
Tuned
Joined: Jul 2009
Posts: 489
Likes: 4
Front Diff Fluid (75w90 or 80w90
One more thing,
I am looking at the F Series Super Duty owners guide and it states to use 75W140 oil in the rear and 80W90 in the front. Why did yall use 75W90 in the front? Which is correct, am i missing something? Lets clear this up..
Thanks again
I am looking at the F Series Super Duty owners guide and it states to use 75W140 oil in the rear and 80W90 in the front. Why did yall use 75W90 in the front? Which is correct, am i missing something? Lets clear this up..
Thanks again
Hotshot
Joined: Aug 2006
Posts: 17,400
Likes: 319
From: Whittier, CA
75W/90 or 80W/90 is basically the same thing. Both are a 90 weight oil at operating temperature. The 75W will not thicken quite as much at cold temps, which is generally a good thing.
Hotshot
Joined: Aug 2006
Posts: 17,400
Likes: 319
From: Whittier, CA
It is all replaced. Except for what may cling to the gears. I know I used a little over 3 quarts. Not sure exactly how much more. But 3 is not enough, that is what matters when shopping.
It ain't cheap either. You will spend around $80 for 4 quarts and the silicone.
It ain't cheap either. You will spend around $80 for 4 quarts and the silicone.
Mountain Pass
Joined: May 2010
Posts: 224
Likes: 4
so buy 4 quarts for the front, 4 for the rear.
Senior User
Joined: Apr 2010
Posts: 151
Likes: 0
From: Suffolk, VA
I just drained and cleaned my rear diff. The 05 truck only has 75k. I noticed everything was coated in some sort grey film. Almost like graphite or something. The oil looked clean as it rained out (I always stick my hand in any oil draining to get a good look at it in the sunlight) but the film kind of confused me. I cleaned it off the inside of the diff cover but left it on everything else. What was the film .... is it the modifier that Ford adds?
Hotshot
Joined: Aug 2006
Posts: 17,400
Likes: 319
From: Whittier, CA
I don't know what that would be, Ken. Moisture is the only thing that comes to mind. Does it feel kind of foamy and slimy? I don't believe it is friction modifier.
Well, I'll bump for ya anyway.
Well, I'll bump for ya anyway.
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Senior User
Joined: Apr 2010
Posts: 151
Likes: 0
From: Suffolk, VA
Nope, not slimy, no foam. Just a dark coating that I wiped off the diff cover. I am not concerned about it because the oil felt smooth with no grit and looked clean in the sun light (made me wonder why I was changing it to begin with). Maybe it was / is just a reaction between the metal and the oil over the last 6 years? I figured someone else had encountered it before though. Thanks for the feedback though.
I read all kinds of great information here!
I read all kinds of great information here!
Mountain Pass
Joined: May 2010
Posts: 224
Likes: 4
Nope, not slimy, no foam. Just a dark coating that I wiped off the diff cover. I am not concerned about it because the oil felt smooth with no grit and looked clean in the sun light (made me wonder why I was changing it to begin with). Maybe it was / is just a reaction between the metal and the oil over the last 6 years? I figured someone else had encountered it before though. Thanks for the feedback though.
I read all kinds of great information here!
I read all kinds of great information here!
mine had the same thing at 90K miles. it could be anything... maybe a little factory gasket material got into the oil, mashed up in the gears and stuck to the pan. but my gears looked brand new, so i am not concerned about it.
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