Rear axle removal/refitting/reusing ?

[Amuso]

On the 84 W123 240TD...

My left drive shaft/axle dropped out of the differential the other day at very low speeds. Actually it was during a left turn out of an intersection so it was almost crawling speed.

It is still attached to the wheel, but my question is. Does the whole axle need to be replaced, or can it be reused and refitted to the differential by means of some parts? I am guessing there should be some mechanism to lock the driveshaft into the diff.

To illustrate Ive borrowed a few pictures from Jeremy5848 in another post.

The axle has dropped out where all the duct tape is in the below picture.

http://www.peachparts.com/shopforum/attachment.php?attachmentid=34301&d=1151636319

I tried to remove the whole axle before towing from the wheel in the below picture.

http://www.peachparts.com/shopforum/attachment.php?attachmentid=34367&d=1151814470

However, I was unable to remove the axle. I removed the center looong bolt and washer from the center of the hub, but could not remove the driveshaft. So I peeled back the booth and let the oil (which I suppose should have been grease) drain out along with about 5-6 metal balls. I guess the outer joint is bad as well as the inner one were it fell out in the first place.

Anyways, I was just wondering if the whole axle needed to be replaced as it is rather expensive. My mechanic seems to suggest so, but I am sure he hasnt actually looked at the problem yet and might just assume the axle is bad. But I doubt that since it hasnt been damaged after falling out of the inner booth...?