Trans and rear differential oil change socket
 

Don't waste time making your own tool like I did. I welded a few nuts to a grade 8 bolt with a 14mm head. The head twisted off.

Went to Autozone (here in Saginaw we call it "Vatozone") and picked up a set of 1/2" drive bits, 12, 14 and 17mm for $11.95.

bah-dah-bing done.

Yup. The proper tool for the proper job. Now don't get me wrong, I have a whole drawerfull of "modified" tools for specific jobs but "make-do" tools usually just make you do extra work/repairs.

Napa auto parts
 

I purchased the 14mm hex key at napa auto parts for about 7$.It is a standard "L" shaped just in the bigger size.
Works well for the money!

I have a set of those large hex keys that I bout at Princess Auto (like Harbor freight). Only use the 14mm.

Just changing oil on my 350SL diff. Hard to find a washer for the filler. And surprised that the drain has no way of sealing except for the threads. Both have been leaking, so I may use a small amount of HT sealant even although I am told it is not needed.

You should have bought the hex key sockets. Attached to a ratchet wrench, you'll get much more torque for install/removal of bolts.

But not if you use a piece of pipe on the hex key for leverage ;)

Interesting thing, is that in the MB Maintenance manual it says to torque both plugs to 50Nm. The filler has a straight thread and a seal washer, the drain has a tapered thread.

Seeing my torque wrench won't fit in between fuel damper and diff anyway, I use my 2ft pipe and push hard for both!

If you can find one of these, they are really nice. They are original to the ponton tool kit and are perfectly designed to give you just the right angle when doing those 14mm plugs.

Original style 14 mm hex (Allen) wrench:



The original Mercedes-Benz Ponton 14 mm hex (Allen) wrench (120 581 06 65) is used for the following drain plugs:

differential (both drain and filler plugs)
gas tank
oil pan
transmission (both drain and filler plugs)

If you can find one of these, they are really nice. They are original to the ponton tool kit and are perfectly designed to give you just the right angle when doing those 14mm plugs. Scroll about two thirds of the way down the page until you see this:

The original Mercedes-Benz Ponton 14 mm hex (Allen) wrench (120 581 06 65) is used for the following drain plugs:

differential (both drain and filler plugs)
gas tank
oil pan
transmission (both drain and filler plugs)

Samstag sales has a 14mm wrench for $55 or so.

http://www.samstagsales.com/images/hz2760.jpg

Having just finished the job, I can see how those wrenches would help. Using the pipe + hex key, works and has one advantage - length can be varied a bit.

Only concern I would have with MB tool, is that it is a bit short and getting plugs out that have been in there for a while might not be that easy. I recall breaking a 3' piece of aluminum tube trying to release the plug on my 300D!