Thanks to J. Hidalgo for warning me that the differential mounts were not a simple job.

While they certainly weren't simple, I didn't have too much trouble, and my home-grown puller/installation tools did just fine. Since a lot of others have asked questions about this and it's all fresh in my mind, I'll try to outline the installation. FYI, I would consider this to be a DIY job only for advanced DIYers. If you're a white collar worker like me, don't do it the day before a big meeting! It is a filthy, messy job if the underside of your car looks like mine! I tried to wear gloves, but the best way to tackle it was to just go for it. If you've done this job, then this write-up will make sense. If you are considering it, then I hope this helps you decide if it's something you want to tackle.

The car: My car is a 1994 E320, but the mounts on my wife's 1990 300E look the same and this installation is probably the same for many many years and models.

The symptoms: My car had a clunk when I chopped the throttle and a quick visual inspection showed that the driver's side differential mount was shot. I could see that the rubber cushioning the inner mount from the outter "shell" was torn and much of it was missing.

The cure: I bought the mounts locally for $11.50 each. Sorry Fastlane... next time... For the puller/installation tool I dropped by my local industrial hardware supply shop and bought:

3 feet of 1/2 x 20 fine thread rod
2 (grade 8) 1/2x20 nuts
An assortment of washers
A 2 1/2 " cast iron pipe cap

I also went to Sears and bought a 1 1/4 " 3/4 drive socket. This socket had an OD that was slightly smaller than the bushing (about .001") and was the key to pushing the old bushings out.

Okay, I supperted the car on jackstands and let the suspension hang freely. I took off the rear and mid exhaust supports and let the pipes hang (I put a couple of wood blocks about mid-way to support the weight) I used a 12 mm hex bit to remove the two big bolts from the back and an 8 mm hex bit on a 3/8 drive extension for the forward mount. There is a 17 mm nut on top and this is where you decide to shed the gloves and just reach up there to feel what's going on!! I had to take off the fuel pump cover to get the driveshaft safety loop off. I lowered the differential as far as it would go to gain access to the bushings.

I drilled (bored) a 1/2 " hole in the center of the pipe cap and this served as the cup that I pushed the old bushing into. I cut a section of the 1/2" threaded rod and slathered everything in Mobil 1 oil so nothing would gall when I started applying pressure. I had considered getting a roller thrust bearing like the one you would use on a harmonic ballancer installation tool, but I didn't and it went just fine. Well, the hard part was getting the old bushings out. They were "Grown" in there. It's just a matter of configuring your puller a few different ways until you get them to move. Drawing the new ones in is easy, and if you've gotten the old ones out, then consider yourself experienced! Make sure you change them one at a time so you can compare the one you are installing to the other one. You need to have it configured correctly and also you need to draw it into the hole to the same depth (there is no stop).

The bottom line: I spent about $20 on my makeshift tools. I think the correct tool would certaily make the job easier, but this is a tough job no matter what you do. My car feels new again. This repair did not just correct the clunk, but the responsiveness and overall feel are significantly improved.

I hope this is useful for someone. I spent about 2 1/2 hours on this, but I think I could shave at least 30 minutes off if I did it again. I suggest this for advanced DIYers only.

Good Luck!
Dennis