Having Panic Attack.....
 

In my recently acquired from ex-husband 83 Mercedes 300d, I am having a panic attack. He took care of all the maintenance, now it is up to me. I don't do the work my self, but have a trusty mechanically inclined person (who really only knows VW's), help me. My anxiety lies in doing the transmission service. I have read and asked and reread and asked again the parts I need, I have read up on the forums on what to use, etc. Am so nervous that doing the service will somehow make the old girl run badly. I am talking from experience with a Dodge Durango, had transmission serviced and it crapped out. I have read on the threads to use synthetic Dexron, but when I went to get the parts today they didn't have this, only Valvoline DEX/MERC ATF, that the parts guy assured me is great. Is this good to use in place of the Dexron III? and for doing the rear differential fluid change my owner's manual suggests hypoid gear oil SAE 90, or 85W90. Parts guy looked it up in his manual and gave me Castrol Syntec Gear Oil SAE 75W90, said the difference between 75 and 80 is negligible. Any words to soothe my fears? Did I get the right stuff? I picked up 10 quarts of the Valvoline ATF, or rather 9 and one non-synthetic store brand, he said mixing one in would not matter. I bought so many because I am doing the power steering filter and fluid and it calls for ATF in manual. You know the old motto, if it ain't broke don't fix it? Am I opening up any cans of worms, or am I on the right road to making her last forever? Sorry to be a pain, but I am new to all this and want to do the right thing, I love, love, love this car!

Forgot to mention car has no issues and since changing glow plugs at winter's beginning runs fantastic!!!!!!

Chill out!
 

You got all the right oils. Are you going to change the tranny filter while you're at it?

On the Diff make sure you can get the fill plug loosened before you drain the old oil out.

The main thing to remember when doing a transmission service is to make sure that you do not get any dirt in the transmission. You also have to drain the torque converter using the separate drain plug. I used Mobil 1 ATF when I did the transmission in the SDL a few months ago and have had no problems.

One trick I learned to do is to put a paint mark on the crankshaft pulley where the torque converter drain lines up with the access hole. This way the next time you do a service you can line everything up right away.

Good luck!

For the transmission you need:

-8 quarts of transmission fluid (you will only put in about 7.3ish total though)
-Filter
-Pan Gasket
-Crush Washers for the two drain plugs
5mm allen key or socket for getting the drain plug on the pan and torque converter out. And an appropriate means for rotating the engine (clockwise only!!!! when looking back at the engine from the front of the car, it should turn towards the drivers side) to get the torque converter drain plug into view down below.

Its a REAL messy job, I'd have the dealer do it if you at all doubt your abilities. Get ANY dirt in there and you'll have problems....it needs to be clean on the molecular level....also, its not a good idea to mix brands or types of fluid...even if the (doesn't know what he's talking about) store clerk says so.

An excellent brand/type of fluid is Valvoline Dexron VI Full Synthetic ATF, its backwards compatible and works great....I am using it in 5 MB's currently with excellent results.


****
For the Power steering you need:

-Filter
-Turkey baster thing (to suck some fluid out of the pump)
-Normal Power steering fluid - Do NOT use ATF in the Power Steering unless you want it to leak!

You can either get a bunch of fluid, disconnect the return line into a suitable container and run the engine in short spurts to "flush" new fluid through, or just suck some out of the pump reservoir and pour some new stuff in a few times on different occasions....its good enough to do that. Don't run the pump dry.

******
For the differential:

It can be a pain to get the drain plugs out, do the top one first so you can be sure you're able to fill it once you drain it. ;)

75w90 of most any gear oil (normal or synthetic) is fine


Good luck! :D

Better to service the trans. than not service it. There is a step by step tutorial over at DieselGiant that you may want to check out. They also have a tutorial on the Power Steering.

http://www.dieselgiant.com/mercedestransmissionfluidchange.htm

The whole transmission service is pretty straight forward and very easy on the 300D.

I like to drain the torque converter. I like to get as much fluid as possible out of there. To find the torque converter bolt it helps to have a helper. One to bar the engine over at the power steering pump (22mm). And one underneath feeling for the drain bolt. It is a hex bolt. Same size as the trans. pan drain. I forget the size. You always want to turn the engine in one direction ONLY!! This would be Clockwise facing the front of the engine. NEVER go the other direction.

Use brake clean and compressed air to clean the pan. Nothing else. And DO NOT touch the bottom of the trans. with the pan off.

It took right at 7.5 qts. to fill mine with the torque converter drained. I have always used regular Dex/Merc III. Using synthetic should be fine.

You have the right diff. oil too.

Do not worry so much, I would not mix regular and syntheyic oils.
clean off the sides and bottom of the trans pan as good as possible before removing it. I change mine in the dirt driveway, and never had any issues because of it.
The gear oil is fine as long as you make a note to what you have in there.
Good luck, and learn a lot!

Should have had your attorney think of the maintenance issue, and provided for it in the settlement.

Regardless, if kept in good order, the '83 300D is an awesome car, and easily worth (5) Ford Tauruses. Anyone here will back me up on that statement.

First off, chill. Once these cars are running well, they are very reliable. Why do you think you need to change the trans and diff fluid now? I agree with the others that it's good to do, but it's usually nothing that you HAVE to do right now.

And, it's not a Dodge...it's built much better.

Relax. No great mystery in either project. Your handy VW friend will do fine and if you crawl under there with him and watch I'm sure you could do it next time yourself.

"Dexron" is a General Motors trademark. GM quit licensing the production of Dexron III in 2006, so the oil companies can no longer manufacture a product and call it "Dexron III." So they are using alternative names like "Dex" instead. Or they call it "Multi Vehicle ATF" and state (in the fine print) that it meets Dexron III specifications.

Thanks for all the advice, going to take a deep breath and put a little faith in my sweet, sweet 300D. :D

Very easy service. I have used Dex III on the last three I have done and used the Valvoline max life products. You will be fine, take your time and relax, not any more complicated than an oil change.

Alert about the power steering
 

X2 and bold "-Normal Power steering fluid - Do NOT use ATF in the Power Steering unless you want it to leak!"
I know the owner's manual says use ATF, but remember that was written in 1983 and ATF formulations have changed. Use power steering fluid!!!
Note that my car is just like yours and I've been driving it 25+ years.

FYI
 

It is far easier to read, when you break it up.

Example:
In my recently acquired from ex-husband 83 Mercedes 300D, I am having a panic attack.
He took care of all the maintenance, now it is up to me.
I don't do the work myself, but have a trusty mechanically inclined person (who really only knows VW's), help me.
My anxiety lies in doing the transmission service.
I have read and asked and reread and asked again the parts I need, I have read up on the forums on what to use, etc.
Am so nervous that doing the service will somehow make the old girl run badly.
I am talking from experience with a Dodge Durango, had transmission serviced and it crapped out.
I have read on the threads to use synthetic Dexron, but when I went to get the parts today they didn't have this, only Valvoline DEX/MERC ATF, the parts guy assured me is great.
Is this good to use in place of the Dexron III? and for doing the rear differential fluid change my owner's manual suggests hypoid gear oil SAE 90, or 85W90.
Parts guy looked it up in his manual and gave me Castrol Syntec Gear Oil SAE 75W90, said the difference between 75 and 80 is negligible.
Any words to soothe my fears?
Did I get the right stuff?
I picked up 10 quarts of the Valvoline ATF, or rather 9 and one non-synthetic store brand, he said mixing one in would not matter.
I bought so many because I am doing the power steering filter and fluid and it calls for ATF in manual.
You know the old motto, if it ain't broke don't fix it?
Am I opening up any cans of worms, or am I on the right road to making her last forever?
Sorry to be a pain, but I am new to all this and want to do the right thing, I love, love, love this car