It's perfect, - the diff should NOT spew oil with the plug removed,- on level ground. 1/4 - 3/8 down is beautious.

Your good, just change it. Not sure where your getting your info, but find another source, - like here.

 

Thanks Jbrew... well everthing I read, even threads on here and the haynes manual said that when I fill the fluid up it should start to dribble out of the fill hole... so i imagined that even though this is the old fluid it should still be up to that level...am i wrong in thinking that?
Also with the rtv... I'm worried that when I put the cover back on... the rtv will squeeze into the diff. Also, i'm not using a gasket, so should I put the rtv on the cover, diff or both?

 

I'd recommend you order a gasket. People here will say just to use the RTV, but I'm old school.

 

Well the rain got the best of me today... so didn't get the fluid changed out. Glc, I called kragen and they can get the gasket for me in about an hour so from their warehouse. Do you have to use the rtv with the gasket? If this dang rain doesn't let up... I may just have to take the truck to the shop for the service... I hate paying to do things that I can do on my own, but I've got no garage and am at the mercy of mother nature right now...
Anybody know what a reasonable price to change it out would be ... if it comes to that...
Thanks again guys.

 

No, don't overfill it. The Haynes manual says that, you sure ?? If I recall correctly, the rear pig is 3/8 and front is a 1/2" down.

I'll go check, actually I think I have that online somewhere, I'll look, hangon.

Crap! Found a pick of what I use to fill them with lol.



Alright hangon, I'll find out from service.

 

Yep that's what haynes says. pg 1-30... "fill the differential housing with the speciified lubricant until it's level with the bottom of the filler plug hole"....
is that too much fluid? I'll hold off on doing anything until i can check back with you guys for sure...
Thanks for looking Jbrew.

 

Well, according to both Hayne's and Chilton's your absolutely correct = bottom of filler hole or until it just runs out. :o

Hang-on , still waiting for the service DVD, I got my info from somewhere ??

 

Hah! I was right lol.

Yea, that's the Ford service DVD for the 97-03 F150's. This has more weight than Haynes or Chilton's of course.

Thought I was going nuts for a minute. I did get them backwards though. The rear is a 1/4" Front is 3/8"

But all them say No Gasket. I'm not sure why, maybe they just won't last ?
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If you have to take it somewhere, I wouldn't go anywhere but Ford. Unless you take it in somewhere and bring your own fluid and watch them. I'll see if I can find a price real quick.

 

Labor time is @ 0.6/ hr. Most likley around 65-85 bucks at the dealer, but you would have to call around. That price includes new fluid from them.

 

Also, do you have a 4x2 139" wheelbase ? If so, you may have a different problem. Do you have a 4r70w and is it leaking from the trans extension housing? You haven't posted these things so I'll guess that's a No.

 

Thanks jbrew... sorry i didn't leave all the info. I have a 4x2 extra cab with the 6ft box... not a long box... not the four door. Not sure what the wheel base is. As far as tranny, not sure of the number... but I just had the tranny serviced and checked out at the ford dealer a couple weeks back, he said I have the heavy duty one... and everything checked out ok on it... And there is no leaking from the trans housing that the slip spline sets in to.... hope thats all the info you need. I know its really a pretty simple service... but anything you can get at the the dealer for less than a hundred bucks ain't too bad, right? Most of the time i go to the dealer I feel like I'm paying a $100 cover charge just to walk in the door!!!

And I'm guessing that the haynes just words it that way for the layman... really it is a bit strange that ford would give the measurement that way seeing that when you fill it its a hole the size of a quarter that is pitch black
... really it seems that it would be a pita to get it exactly 1/4 inch below the hole.

 

There was one TSB (TechnicalServiceBulletin ) that described a vibration issue, but it wasn't specific to speed. A break down of fluid vibration, specially in the 9.75's (which you have) is specific to 55-65mph +. There's been quite a few posts in the past in the powertrain forum on the site -

https://www.f150online.com/forums/other-powertrain-15/

The easiest way to fill is pre-measure in liters/pints, whatever your comfortable with, then squeeze it in their. You will see what I mean by squeeze when you fill it lol. Anyway, should come out perfect because when you pop the rear cover, you can drain it completely and even wipe out the bottom. Just get it as close as you can, at least now you know where it's gottuh be.


BTW - You'll need a putty knife as well, - to slowly pry the rear cover off to drain.

 

If you use a gasket, put a very thin coat of RTV on both sides of the gasket to stick it in place while you are rebolting the cover. It's a lot less time consuming than using just RTV, which requires a setup time before bolting the cover on. Sorry, I just don't trust using RTV only on that thing.

 

Thanks for clearing that up, I would have never guessed.

I know what your saying tho buddy. I could go either way if it was a well made gasket.

 

The gaskets that Autozone sells are Fel-Pro, as good as any.