1981 300D

Hi Guys,

I just changed the differential oil. Straight forward procedure but it could be messy. I didn't need to raise the car. I was expecting a thick, slow-flowing fluid...but when I turned the nut the last thread....splash...a rather forceful stream of oil came out. So be careful and have plenty of rags and newspapers.

Surprisingly, the hex nuts were easy to remove. Maybe the previous owner changed the fluid regularly as it looked like dark honey, not black as I was expecting.

I refilled with Mobil 1 synthetic gear fluid 75W-90. It took a little more than 1 quart. Torque for both nuts was set to 43 ft-lb.

Tools used:

-3/8 drive, 14 mm hex bit (bought it as a set in AutoZone with 2 other bits for $8)
- 3/8 drive, 18 inch long breaking bar
-3/8 drive ratchet.
-3/8 torque wrench.

And yes, plenty of newspapers.

Kefer,

I am curious about what you used to get the new stuff back in the side of the differential. I have done this a few times on my cars and have yet to find an adequate (meaning I spill relatively little of the new stuff on me) method. Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

I poured the new oil directly from its bottle. I just nipped a little bit off the conic tip and tilted it inside the differential.

There is enough room to tilt the bottle upwards so you can get roughfly 90% of the contents inside the differential. I had bought a second bottle so I put the remaining 10% of the first bottle in the second bottle.

I checked with my finger and the level was below the plug maybe 1/2 inch. I tilted the bottle carefully again and squeezed gently until a small amount of oil came out the refill plug. Cleaned the excess...torqued the plug to 43 ft-lb. And that was it.

Kefer,

I guess I can see how one of those long thin bottles with the pointy spout might work better than a regular quart oil bottle. I use Redline oils for the manual transmissions and the differentials on my cars and that stuff comes in a regular, round, stubby, fat, quart oil container.

Maybe the differential oil needs to be done with Mobil 1 stuff. Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

you can buy a nifty little pump with a lenght of flexible hose on it that screwa on the top of a gallon container of gear lube at any large auto parts store...
William Rogers...

Hey, I just changed my diff. lube last weekend. I was all excited after removing the plugs, until I approached the fill hole with the "big mouth" amsoil bottle!
Anyhow, I grabbed one of those lube pumps, too. WORKED GREAT!

lol...... when I finished replacing the driveshafts on my 300D I had put the cover back on before loosening the bolt. I was under my car with the socket wrench (non-ratcheting for more leverage) trying to undo the bolt with my legs. I guess the PO never had the differental oil changed

On second thought I doubt he even knew that the drive shafts existed, the boots were pretty beat up.

__________________
2005 Audi A4 1.8T CVT -Silver/Black "Siegfried"

1982 300D - Silver/Blue "Ralph" -For Sale:
http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/119226-1982-300d-sale.html#post852260

1989 VW Diesel Jetta Blue/Blue "Bodo" RIP

When I removed the refill plug...I checked the bottle-differential relationship before draining the old oil to make sure I was going to be able to refill.

I had a big scare though. I tought the blue conic tip in the new oil bottle was secured. BIG MISTAKE. As I was checking for clearance...that blue tip fell into the differential!! I carefully tried to pull it back to no avail.

I said.."what the heck" and opened the drain pulg...fortunately tha plastic blue tip was washed away along with the old oil. Cheated death. For a moment I thought it was going to be a long night.

The lubricant in a differential or manual transmission will not turn black like engine oil. There are no byproducts of combustion as in the engine. That's why you can run the lubricant so far.

Several years back, I bought a five gallon bucket of hypoid gear lube at the wholesale oil dealer. Then I went by the farm and ranch store and bought a pump that goes on the top of a five gallon bucket. It has a hose and a hook shaped spout that hangs nicely into a rear axle fill hole. Hang it in there, pump 'til it starts to overflow and your done. When not in use, I shove it under a bench with a heavy cloth over it so that it collects no dust.

Have a great day,

Nice... my project on my SLK 230 was a pain. Whoever tightens the fill plugs at the factory is a sick, sick person. I bought two quarts of MB 85w 90 at the dealer for $34 per quart (the book says 1.2 quarts). It took me two special orders thru a local tool supplier to get a 14mm hex that would work (total $25). Maybe next time I will just take it to the dealer. But then, I would have missed the experience.

Kefer,

Thanks for the info on Auto Zone for the 14mm Allen. I just refuse to pay the $32 for the special Hazet German wrench with the oil plug wrench on the other end.

I am not a fan of Auto Zone, but if the price is right...you have to do it. Besides, how many times are you going to use the 14mm Allen anyway?

Off I go....

__________________
'06 E320 CDI 51K miles
'02 VW Jetta GLS TDi 120k miles
'99 Ford E350 7.3L Powerstroke 200k miles -sold
'84 Euro 300D 5 spd manual 317k miles - sold

A lot of people have used a 14 mm hex head bolt and vice grips as the wrench.

__________________
Jeff Naumann
Torrance, California
1972 220D 138k miles (sold)
1982 300SD 263k miles
1989 BMW 750iL 183k miles
1993 Dodge D250 Cummins 5.9 202k Miles

I don't think the PO ever changed the differential fluid in my car. I used a 14mm 1/2" hex driver from Snap-On and a 18" breaker bar to free the plugs. I used a cheap pump for a stubby quart bottle to fill the diff with M1 75W90. I changed it after 10,000 miles and solid debris came out, changed again after 10,000 miles and some more solid debris came out - the fluid dark both times.

I recommend to anyone that hasn't changed the diff. fluid in a while to change out the synethic fluid early and several times before running it for a long time.

Brian

Anybody else hate AutoZone???

Kefer,

I can't find any AutoZone near Cleveland that carries even the 14mm hex bit alone? Which Auto Zone did you get your at? Do you have a part number...because I can't even search for a hex bit on their web site.

Thanks,

__________________
'06 E320 CDI 51K miles
'02 VW Jetta GLS TDi 120k miles
'99 Ford E350 7.3L Powerstroke 200k miles -sold
'84 Euro 300D 5 spd manual 317k miles - sold

I picked up mine at AutoZone tonight. It is on the rack with the rest of the sockets/tools in a 3 socket set, I believe 14, 17mm and one other I can't remember. It is in a red paper and plastic hanger, OEM parts, about 8 bucks. Hard to find, but it should be there.

Thanks for the tip on Autozone for the hex socket.......I was poised to buy one from Snap-on for about $20.

JCD