Hello again everybody,
I would like to share how I swapped a driver side axle in my 1980 300SD. This is a 116 chassis but the process should be similar to most models.

A little history... My wife drives the car for the most part and she let me know that there was a dragging/scraping/clunking noise coming from the rear end. I looked underneath and noticed that the drivers side boot had cracked and was leaking fluid in the surrounding areas. I misdiagnosed the noise as a bad CV joint... it turned out to be the sway bar link dragging on the rim. Needless to say, I still have a noise but the axle is no longer leaking. I was able to source a good used axle from Pick N' Pull for $30 so that was the only way to go. Follow along as I show how I changed my axle.


- Start by jacking up the back end, make sure to support the car by the body, not the axle or suspension. Take the back seats out and locate the upper shock mount. Take the nuts off of the top of the shock and the suspension should droop a little as the tension is released from the shock.


- Drain the fluid from the differential. A great piece of advice from DieselGiant is to remove the fill plug first, then remove the drain plug. This is so you don't get stuck having a differential with no fluid and no way of getting fluid back in if the fill plug is frozen.


- Loosen the differential cover bolts, use a jack to support the diff and remove the 4 bolts holding the differential to the frame.


- Take the differential cover off to reveal the gear set. Locate the lock ring/clip. Mine is located just to the right of the leftmost spider gear in this picture. You may need to lower the diff to get a good angle on the clip.


- Close up of the clip to be removed. The easiest way for me to remove was to use two small electronics flathead screwdrivers and just push on each side. The clips could fly out so make sure you keep an eye on where it lands.

The next step is to use the floor jack to push the differential as far up as it will go -- this is to create distance between the hub and the differential so that the hub side of the shaft will come out easily.


- Locate and remove the bolt from the center of the hub. This is the only bolt holding the axle shaft to suspension.


- Once the bolt is removed you can gently tap the axle out of the hub using a socket extension and a hammer. Make sure to completely push all of the splines out of the way and the end of the axle is completely out of the hub flange.


- Now you can tug on the axle shaft and it will come out of the differential fairly easily.


- This is the axle I removed from a gas Mercedes with a 116 chassis. It is shaped differently but the shaft size is the same, as well as the spline count. The seals on the end match up the same on both axles. Notice the severe cracking on the older axle, the newer one seems like it should last a while.

The process to install the newer axle is exactly the reverse. Make sure you put the differential side in first - then the hub side, this is very important.


- The final result. Not bad for $30 and 4 hours.

I hope you enjoy and please leave feedback if you found this helpful.

Thanks,
Mick

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1980 300SD, 190K miles -- Soon to be on WVO
1989 GMC Suburban 6.2L diesel on WVO and B99