Rear diff leak?

[alexwasserman]

Hi all,

After a recent oil change the mechanic reported a rear diff leak. The weather has been a bit too nasty recently to go crawl underneath and double check it.

What's the recommended fix normally? Just tighten down the bolts, or remove the cover, and replace the gasket? Does it require replacing the cover or bolts as well typically?

 

[07navi]

Same bolts are fine, tightening them might help but probably not. year? make?

 

[alexwasserman]

2007, XLT, 200K miles.

 

[Plati]

My 2003 was leakin back there ... spots on the driveway alerted me. One immediately blames the gasket. On that year you have to remove the whole damn diff to a bench to replace cover gasket. Other parts have to be removed also. Someone advised me to clean it all up and find out where it was leakin from. Smart! Did that. I think I used carb cleaner and some soap and brushes. Then it was obvious that the leak was at the seal for 1/2 shaft on the side. I monitored it and determined that 1) it only leaked when i drove more than 40 mph 2) it didnt leak much. So , the age & condition & vehicle usage profile (I only use locally, usually under 40 mph) of the vehicle considered ... I have elected to keep an eye on it and top it off as required. Thats worked well for a year or so. I did change the fluid once and it was less than a cup low.

 

[Boostedbus]

Make sure it’s not a leaking pinion seal also and if so check the U-joint well. I’ve had a frozen U-joint take out a pinion seal before on an old F250. I guess from the vibration and oscillation.

 

[07navi]

At 200,000 miles I doubt if it is the cover gasket. They rarely suddenly start leaking because they don't wear so I suspect it is a rubber seal which requires much more work to replace. Shaft seals can only be replaced and not fixed.

 

[alexwasserman]

Thanks for the help here.

I filled it up, took less than half a quart, and after squirting that much in a fair amount leaked out.

That said, it's a mess all over.

I also need to replace the sway bar bushings, so I'll order those and see how much oil has leaked out in a week or two.

If it makes a difference, this is the tow-package diff as well. The 3.73 / 9.75 model.

 

[07navi]

Looks like both axle seals. A cover leak wouldn't wrap oil around the sides like that.

 

[alexwasserman]

And, just so I understand properly - looks like the replacement here is:

1. Remove both rear wheels
2. Remove both rear brake calipers
3. Remove the rear wheel hubs and fold out the way
4. Remove the diff cover and drain the diff
5. Remove the rear axles
6. Replace the seals
7. Do all the above in reverse to put it back together again.

In addition to which I also need to replace the rear sway bar bushings, and replace the cam phaser since it's ticking pretty loudly now, and probably all the plugs at some point.

This car is becoming a lot of work, given how incredibly reliable it's been so far up to 200K.

Trying to work out if it's worth the work and then keeping it for another 50-100K.

 

[Port Tack]

Ford dealer is going to replace both axle seals on a vehicle that I intend to purchase (2013 expy el xlt). He says they are leaking. Is this atypical for a truck with 107,000 miles on it? Would others here think the truck must have been ridden hard for these seals to be leaking? The truck is like new otherwise.

 

[Vancouver Bob]

Sounds like this may be a semi common problem...

https://www.expeditionforum.com/threads/rear-axle-seals-leaking.28615/

https://www.expeditionforum.com/threads/cv-axle-seal-leaking.20666/

Not positive, but I think the seals go on from the outside of the differential housing. When I had my differentials worked on they were waiting for seals before they could re-install them but the differentials were all assembled and buttoned up.

 

[Trainmaster]

There's a rule of replacing the bearing when replacing a seal. The logic is that bearing wear has created movement that trashed the seal. But seals can fail for other reasons too, including manufacturing defect, debris, or poor design. When the seal's pulled, the wearing surface has to be inspected. If the seal has worn a groove in that surface, it too has to be replaced. So hammering new seals into the housing only guarantees to repair the problem for a short time if the proper measures are not taken.

 

[da1duc]

There's a rule of replacing the bearing when replacing a seal. The logic is that bearing wear has created movement that trashed the seal. But seals can fail for other reasons too, including manufacturing defect, debris, or poor design. When the seal's pulled, the wearing surface has to be inspected. If the seal has worn a groove in that surface, it too has to be replaced. So hammering new seals into the housing only guarantees to repair the problem for a short time if the proper measures are not taken.

Cannot find that stub shaft bearing anywhere in the parts list. Does anyone have the number for it?