Oh No. A front differential oil leak

[shortbed]

While reinstalling the front axle spindle of my 4wd F150 after replacing the ball joints I noticed an oil leak from the axle shaft itself. Apparently a seal in the differential was damaged. I've been looking for information on this seal and how to repair it but no luck so far . . . Any suggestions?

 

[fatherdoug]

http://www.fordtruckfanatics.com/forum/showthread.php?t=29290

Check this section out. Page 15-30-4. Could be just the spindle bore seal on the axle shaft?

 

[shortbed]

Father Doug,
I so wish it was.
I fear there is a seal at the differential itself and that the end of the spindle, when pushed back in, disturbed that seal.
I think the spindle bore seal is more of a dust seal. The inside of the axle housing was dry when I pulled the spindle out and then started leaking after the spindle was put back in.
I think I need to pull the spindle again, break open the differential, find that seal, fix or almost certainly replace it, reset the spindle and close it all up again and it feels a bit like a being kicked by a . . . well just kicked.
But your manual was terrific and thanks for sending it.
Have you ever opened that front differential and messed with an axle seal ?

 

[fatherdoug]

Father Doug,
I so wish it was.
I fear there is a seal at the differential itself and that the end of the spindle, when pushed back in, disturbed that seal.
I think the spindle bore seal is more of a dust seal. The inside of the axle housing was dry when I pulled the spindle out and then started leaking after the spindle was put back in.
I think I need to pull the spindle again, break open the differential, find that seal, fix or almost certainly replace it, reset the spindle and close it all up again and it feels a bit like a being kicked by a . . . well just kicked.
But your manual was terrific and thanks for sending it.
Have you ever opened that front differential and messed with an axle seal ?

Sorry, I think I was looking at the wrong seal.

I did replace the front axle ujoints on a '79. The axle shaft slid out and right back in, with no leakage.

 

[holtz]

A lot of times when you pull the axle shafts out and put them back in there is usually a lot of dirt and small rock build up in the tube and the end of the shaft can push some onto the seal and can also get some debris on the splines and can damage the seal. I have cleaned out many of axle tubes and the amount of crap that was in there will surprise you. I always enjoyed replacing those seals, knocking them out is easy putting them back in takes a little finesse.

 

[shortbed]

Holtz.
I want to hear about THAT!
Can you tell me what to do?
I'm figuring I take off the dif's face plate and drain the oil.
then, though I wish wish wish I didn't have to I'm guessing I have to pull the spline back out and somehow replace that damaged seal that is holding the gear oil within the differential.
And THAT, I'm guessing, is the little finesse part.
Tell me about THAT. What little trick did you learn, if you remember, on how to get that new seal in there. (If that is what you were referring to)

Jim in the Sand Hills of North Carolina

 

[holtz]

This picture is a little crude but I hope it helps.

 

[holtz]

To knock them out use something long and should have a slight pointed curve at the end and they knock out into the diff housing, after they are out I used solvent soaked rags and went through each tube a couple of times to clean all the debris out of them.

 

[shortbed]

Holtz,
That's beautiful. You've probably had situations like this . . . when you're in the dark and then you get the information you need. It's like a lighthouse. I really appreciate you doing all that. I'm guessing I'll be able to see exactly how the other seal is seated, the one on the passenger side and seat mine the same.
Also: I drove my truck for about 100 yards after putting that spline back in the first time, got out and checked it, saw the oil, drove it back and parked it. I'd forgotten I still had it in 4wd, the hubs locked and now I wonder how much of a risk I'll be running if I drive it the fifty feet into my shop (even out of 4wd). I have this image of that seal all chewed up in the gears. It gives me a cold sweat just thinking about that. Would you risk it?

and Holtz, seriously . . . thank you again for that drawing.


Jim

 

[holtz]

The seal is still in one piece, it is just leaking so driving it to your shop is ok. I have seen people driving on bad seals for a long time, it just makes a mess and gear oil seems to trap everything.

 

[shortbed]

Okay, I'm almost there. On your drawing you're replacing the seal on the passenger side of the differential. The rod is coming in from the driver's side. If there was a seal already in the driver's side you would have to pass the rod through it, put the seal on in the differential housing and then tap it in place on the other side. Can all this be done with the differential's gears still in there?
If I am replacing the seal on the driver's side do I have to come around from the other side (pulling out the hub's guts on the passenger side) or is there a way to seat driver's side seal from the driver's side?

And anyone reading this would think: 'Why doesn't the fool just take off the differential cover and find out?' And the answer to that is a longer story than we need to hear, but it would help me a lot if I knew before I got in there. Do you remember these details Holtz?

 

[holtz]

Yes, you have to remove the carrier out of the diff. housing and make sure the bearing caps are marked and go back on the same way and yes the drivers side gets installed with the tool coming through the passenger side tube.

 

[shortbed]

Well, Holtz, I'm going to give it a shot. I'm planning on bringing my truck down from where it's been sitting so that I can work at it where I live. I'll let you know how it goes.

 

[shortbed]

New Plan:
I decided to open the differential and have a look first. I did and it seems like more than I can handle right now. I've never messed with these gears before and I need more time to get clear what I would do in there, so this is what I'm thinking. Putting the plate back on, putting enough oil in there it isn't dry and yet not dripping out my axle and driving it until I find a back up vehicle. I've started looking anyway.
I'm figuring that as long as it's not in 4wd those gears won't be turning, the spindle won't be turning and everything can go on quietly and peacefully until I have another truck and can work on this one without anxiety.

How does that sound . . . ?

 

[jw818]

It is really a lot easier that it seems. Granted I pulled my axle out when I did it I did not run into any problems. Remove the front cover. Pull the gears out as previously mentioned. Knock the old seals out and put the new ones in. I used a large socket attached to two long extensions to install the new seals. Throw the gears back in and put the cover back on. And if you dont want to repair it quite yet and dont want to worry about the oil leaking out and burning out the axle, take the front driveshaft off until its fixed.

 

[shortbed]

Bless your heart jw. I reckon once I've done this once or twice pulling the gears out of my front differential and reinstalling them would be as easy as 'pulling them and throwing them back in', but I've never in my life been as close to those gears as I was last night and my manual doesn't even begin to explain any part of how to do it, but thanks for the pep talk.

 

[holtz]

I actually have a front axle I need to do a rebuild on so I will take plenty of pictures and post them for you so you can see that it's really just a walk in the park ..

 

[jw818]

I agree, if I was smart enough to put pictures on here I could show you how easy it is. I was very hesitant at first but after reading some good information on forums it was a breeze. My first attempt was on my '75 jeep and I have yet to have an issue running her in 4wd. Second time was on my '78 f150. Remove the 4 bolts and after a little pulling the gears will come out. Just keep track which caps you remove and where they were and torque them back down after the seals are in. Just think of it as replacing the gasket on the rear diff, you have to pull out the whole carrier and everthing lines back up when reinstalled. Just dont mess with the pinion gear and you will be good.

 

[shortbed]

You guys are both sweethearts and I am looking forward to doing this. I'm a little bit of a coward when it comes to this stuff. I start, get scared, close it up, read, ask a million questions, start again . . . go a little farther . . . that's just the way I am. If you need a wall repaired I can do it with my eyes closed, but a lot of this stuff is really new to me, so I very much appreciate you guys watching my back. I am looking for another vehicle. I hope to have one soon and that will take the heat off everything I do to this truck.
I'll keep you posted and thank you, really, thank you both again

 

[holtz]

I could have used your expertise when I was building my shop, I definetly am no carpenter, But it hasn't fallen down yet...lol