Due to a vibration at high speeds, and approximately 3/32" to 1/8" of side-side wobble in the yoke on the back of my transfer
case, I removed the driveshaft and yoke to investigate and repair.

- 1999 Mercury Mountaineer
- 302 / 5.0L v8
- AWD
- 4r70w transmission
- Transfer case was rebuilt ~20,000 miles ago with "hard parts" though I don't know every specific part that was replaced.
- Drivetrain has around 170k total miles.
- U-joints appear fine

After removing the driveshaft I removed the nylon-lock bolt which holds the yoke onto the end of the
tailshaft, and discovered that the rubber washer which sits under the metal flat washer had disintegrated. Does this washer
just allow for a cushion between the nut and tailshaft to reduce vibration?

At this point I also discovered that approximately 2/3 of the wobble is due to the yoke plate splines being loose on the Tailshaft
splines, and the other 1/3 of the wobble is due to the Tailshaft itself being loose inside the inner race of the bearing.

The tailshaft seal is also shot (spring fell out in pieces) although the rubber is in decent shape and haven't noticed a leak in this
area. This is the "non-booted" seal, which is only about 3/8" thick overall and does not protrude at all from the case. Replacing
the seal only would not a problem - I have one on hand now.

The front transfer case seal apparently started leaking recently, and fluid level is about 1" low.

Replacing the bearing looks like a big task, and I am not sure of the best way to go about it. I purchased a bearing that the
parts store "thinks" is the right one, although its ID is .07" larger than my tailshaft splines OD .

The bearing also slides fore/aft on the tailshaft about 1/2". As a result, this allows the yoke to slide forward on the shaft, which
is letting the yoke plate grind alumimum off of the back edge of the transfer case as the shaft spins.

Is the tailshaft bearing what hold the yoke from sliding forward more than it should? It is just a regular round-ball bearing, which
does not seem like the correct type of bearing at all.

Since the bearing slides along the length of the shaft, I assume this means the case is worn, and I need to replace it as well.
However, the bearing itself does not appear worn and the inner race spins very freely while the outer race is still. If the
bearing moves this freely I can't imagine why the inside of the case would be worn beyond the "press fit"?

Questions:
* Does the shaft bearing stop the yoke at its furthest forward movement? If not, what does hold it from sliding too far forward
and rubbing the case?
* Ford can no longer get the case - will a transmission shop be able to make a repair?
* Where can I get the rubber washer if I do the repair myself?
* How do I replace the bearing, if I do the repair myself?
* Are there any of the "repair sleeves" made for the ID and OD of the tailshaft bearing in this transfer case?
* how much slop is normal in the two sline gears, and can I replace these doably/economically? I would think
these should be a pretty good fit, just loose enough to slide together.

Thanks! Pictures below: