I called Autozone and all they have in Mobil 1 differential fluid is 75W140. http://www.mobil.com/USA-English/MotorOil/Other_Products/Mobil_1_Fully_Synthetic_Gear_Lube_75W-140LS.aspx

I don't have a specification manual anymore, but I thought it was supposed to be closer to 90 weight oil. Is 75W140 too heavy for a differential?

Stick with the 85W90. IIRC I got mine from Walmart.

That sounds better to me--and probably cheaper.

I should probably add as well that after switching to the Mobil1 Synthetic the 'whirring' noise on the freeway I was getting in the 300TE disappeared. The fluid didn't 'look' too bad either...So...I'm happy with it.

Well, I bought the Mobil 1, jacked up the car and discovered that the 17 mm Allen I used on my 400E was too big for the E420 drain bolt. You were right, Army. I think it looks closer to a 14 mm. Can't figure out why the difference between the two years. The part numbers for the plugs are the same for both years (A 186997 00 32).

The hardest part was getting the bottle high enough to pour into the fill hole. The 2 foot hose extension that you can buy at Autozone is absolutely useless for this (don't waste your money). It leaks all over the place and you still need to get the bottle above the fill hole.

I had to use two bottles and found that I could squeeze enough directly out of two bottles to fill it. You have to jam the bottles up toward the bottom of the body. There's nothing like getting your shirt soaked in Mobil 1 on a Sunday afternoon. At least it wasn't Skydrol.

Oh yes I've been there
 

Yes I had to do exactly that on my W123 - only I think it was on a Tuesday morning... good fun isn't it? Still at least you know it has been done properly.

Take a look under the car once in a while over the next month or so to make sure there are no leaks (particularly from the plugs) - particularly after a long run and the oil has had a chance to get warm

It's nice to know that I'm not the only one. I used Teflon tape on the plugs, but I will check them periodically too. Thanks.

I am going to do this this weekend, any need to use locktite on the plugs? If so what color?

Your Mercedes,Your Pleasure
 

BUT,there's no way In hell I'd risk putting ANY Loctite product on the Differential
Drain Plugs.
(They're "Tapered" Plugs ,Larger towards the "Outside",which is why they can be SOOOOOOO Tight)
[Using Loctite MAY Insure you'll never get them out again!]

"Level" is the correct way to check Differential Fluid.
(The Factory is sorry that you don't have a "Lift",BUT that's your own Problem)
(You really should have taken it to the "Stealer".)

EmeryDC8,

4 Wheels on "Rhino" ramps.
You can pick up a Plastic spring loaded hand Pump that'll fit Quart Bottles.
(Then the Feed Container can be Upright AND below the "Diffy".)
[I use the Picture of the Yamaha pump 'cause it's what's in the Garage]

Are the Rhino Ramps short enough to slide in front of the rear wheels too?

I Just Love it ,when I 'Ave to eat crow.
 

Rhino Ramps Height specifications in Below Picture.


'Silly Me, I use the 3K Lbs Floor Jack on the Rear Jacking Pads (In front of Rear Wheels) and then Hand Place the Ramps under the Rear Wheels.[Facing Backwards]
(I Gotta be creative,since I'm "Lift Challenged")

And My "Murphy" consultant tells me She'll get Two Weeks all expenses paid in Paris this Spring,If:
"You'll only just try BACKING all four wheels at once onto the Ramps".
(Nod,Nod Wink,Wink)

(For Our Newer,Less Suicidal, Members: NEVER,AT HOME or ABROAD, try for the "Four at Once" "Ramp Lift" METHOD.'TOO MUCH RISK OF CALAMITY to Chassis.)

No need for loctite the plugs, they are conical (much care is necessary when you tighten them back, they may break everythings)

I have my diff out of the 87 TD and will be reinstalling tomorrow. I guess I'll pick up synthetic fluid since it only needs 1.2 qts. I have attached a hose to the container and squeezed into fill hole on other projects. Having the diff out on the bench makes this an easy service.

(I am replacing diff bushings and SLS accumulators).

There are 2 options. One is to buy a suction gun at $12-20. The other is to use a section of hose (3/8?) firmly placed onto the cone shaped cap, or drill a hole in a cap and have the hose tight fit inside.

Use of the suction gun is self explanatory.

The hose method on the bottle allows you to squeeze the fluid UP into the fill port. This has worked like a charm for me for many years. It you are making a mess then your procedure needs to be amended.

Best of luck.