Differential Leak

Newbie here,

Two quick question:

1. 99 EB Expedition with 101,000 miles, 2wd. About 6 months ago I changed the differential oil and resealed the differential cover. I just noticed that I have a leak (just a few drops overnight) leaking from the bottom of the differential. Thought I had not sealed the cover well but I looked under the differential and it appears the leak in coming from the seal around the drive shaft into the differential. Is there a seal or is it something else?

2. Noticed the auto leveler compressor is running more often then normal (still not that bad) is that a sign of a leak in the air bag?

Also, I'm in the process of repairing a few of the other problems that others have highlighted:

Blow subwoofer speaker -- replaced speaker with JL Audio and resealed box -- works great
Worn lower ball joint -- will repair next at tire rotation
Plug Change -- sounds like it maybe more than I can handle -- patience wise
Intermitten Odometer -- saving for a latter time
Rear window wiper not working -- saving for a latter time

As usually, lots of brakes, airfilters and oil changes -- normal maintenance.

Newbie here,

Two quick question:

1. 99 EB Expedition with 101,000 miles, 2wd. About 6 months ago I changed the differential oil and resealed the differential cover. I just noticed that I have a leak (just a few drops overnight) leaking from the bottom of the differential. Thought I had not sealed the cover well but I looked under the differential and it appears the leak in coming from the seal around the drive shaft into the differential. Is there a seal or is it something else?

2. Noticed the auto leveler compressor is running more often then normal (still not that bad) is that a sign of a leak in the air bag?

Also, I'm in the process of repairing a few of the other problems that others have highlighted:

Blow subwoofer speaker -- replaced speaker with JL Audio and resealed box -- works great
Worn lower ball joint -- will repair next at tire rotation
Plug Change -- sounds like it maybe more than I can handle -- patience wise
Intermitten Odometer -- saving for a latter time
Rear window wiper not working -- saving for a latter time

As usually, lots of brakes, airfilters and oil changes -- normal maintenance.
1.There's a seal in that particular place that you talk of
2.Air suspension compressor running longer typically means a leaking bag or solenoid, have you ever let the vehicle just sit there for a few days to see if it loses air(noticed by ride height).

There are seals where the driveshaft connect with the rear diff and the tranny, and the auto leveler, could be a leak or a solenoid not reading properly. Changing plugs isn't too bad, rear wiper motor is one of the easiest things to do. Look at the "Rear Wiper Motor" thread posted earlier and I gave simple instructions on that changeout.

There are seals where the driveshaft connect with the rear diff and the tranny, and the auto leveler, could be a leak or a solenoid not reading properly. Changing plugs isn't too bad, rear wiper motor is one of the easiest things to do. Look at the "Rear Wiper Motor" thread posted earlier and I gave simple instructions on that changeout.
1.there are no seals where the driveshaft connects to the diff. those are called U-joints however there's a seal at the pinion yoke
2.solenoids are not sensors and do not provide input to the module that controls Air Suspension i think you're confusing them with the height sensors
3. if coil on plugs your in for a treat on changing those spark plugs especially if it has rear a/c and heater

1.there are no seals where the driveshaft connects to the diff. those are called U-joints however there's a seal at the pinion yoke
2.solenoids are not sensors and do not provide input to the module that controls Air Suspension i think you're confusing them with the height sensors
3. if coil on plugs your in for a treat on changing those spark plugs especially if it has rear a/c and heater

Thanks guys,

Just got a call from the wife..."I think something is wrong with the Expedition, when I put it in drive or reverse I hear a funny clunk"

Sounds like u joints, I hope not the transmission. Weekend project coming up.:banghead:

the leak could be a sign of a pinion bearing failure. when you drop the driveshaft try and wiggle that yoke around and see how much movement there is up/down left/right and in/out. there should be very little. if there is more than that i would take it to a shop and get it looked at.