722.6 Transmission Fluid Change

[Southern]

Since the local Mercedes dealer won't even consider doing a trans fluid change unless you have 100K miles on your car I decided to do it myself.

Thanks to the advice from the members and moderators, I sucessfully changed the trans fluid, filter & gasket on my 98 E320 with 80K miles.

Since I do not have the diagnostics equipment to verify the temp of the trans fluid (80 deg. C), I took another approach. I purchased the transmission dipstick (special tool) and measured the level with the engine cold. The level came up to the 25 deg. C mark. Then I drove the car for 30 minutes and checked the level again. The level was half way between the 80 deg. C mark.

I pulled the drain plug from the transmission pan and drained the fluid into a container. The fluid was filthy, it was a dark brown with no hint of it ever being red. I removed the transmission pan and cleaned it out very well. There was about 1 mm of "muck" on the bottom of the pan. I then pulled the drain plug from the torque converter and drained the fluid into a container.

I installed a transmission pan magnet in the bottom of the transmission pan, installed a new filter and gasket and buttoned everything back up.

I measured the amount of fluid that I took out (7.3 L) and poured 7.3 L of new trans fluid back in. I checked the fluid level with the engine cold (the level came up to the 25 deg. C mark). Then I drove the car for 30 minutes and checked the level again (the level was half way between the 80 deg. C mark).

As always I checked and double checked for leaks.

I do recommend that the trans fluid be changed every 60K miles (as mentioned before from other posts) due to the amount of "muck" and the condition of the trans fluid (filthy). Even though the trans fluid is synthetic, the "muck" and "filth" will eventually plug the filter (which is small in size) causing transmittion failure.

[joe p]

Ray,
I would remove that magnet that you installed. There is an electronics plate right above the valve body with speed sensors and temp sensors. There are also solenoids right there.
I am not saying this will definately cause a problem, but it would not suprise me.
Brian

[Southern]

Brian,

I would agree with you if the magnet was strong. The magnet I used is a Mercedes magnet and now recommended by Mercedes. It is about the size of a business card and about as weak as a kitchen magnet.

I placed the magnet at the bottom corner of the pan (near the drain plug). Avoid placing the magnet near the inlet of the trans filter to avoid the filter from sucking up the muck.

My Chevy Astro came with a transmission pan magnet from the factory. The magnet does a great job of collecting the muck. When changing the trans fluid and filter, I always clean the magnet which is very filthy.

Way to go Ray on changing your own tranny fluid. I'm glad to see I'm not the only one who is replacing the so called lifetime fill tranny fluid.

I did pretty much the same thing you did on the fluid level measurements, I think it's a very worthwhile project and something that most anyone can do.

Keep up the great work Ray, and of course you have one of my dream cars (98 E320). I love my 95 E320 but I can't help but to drool just a little everytime I see a "bugeye" E class. Enjoy it!!

Dale

A habit I started practicing years ago is to siphon/drain the trans fluid from the pan with every engine oil change. I get usually 35-50 % of the trans fluid changed doing this. At 30,000 mile intervals I pull the pan and replace the filter, wash out the pan sludge (not much there) and wipe off the magnet. This is the cheapest maintenance I can do for any of my cars. The trans fluid always looks and smells fresh, and never a tranny problem. I agree with you, 100K miles before a change, a "permanent fill"; no such thing !
I do this for the power steering as well. That fluid gets boiled and there isn't much to begin with. I've done this for my SLK

The AT dip stick tool; is yours like mine, about 2+ feet too long?
I had three guys check the part number, after I purchased it, and the Part Number on the bag is correct ! No wonder you can not consider it anything other than "a tool".

When I purchased the dipstick and they brought it out, I told them I didn't want to check the rear-end grease with it.

Yes, it's way too long but works great telling the fluid level!!

[jgl1]

Part number for that M-B magnet?

[Southern]

After I changed the trans fluid on my Mercedes, I realized that it was simpler than on my Chevy Astro. The pan gasket for the Mercedes is molded to fit around the lip of the pan. On my Chevy I need to spray some high tack on the pan flange to get the gasket to stick so that I can screw in the dozen or so bolts. I also had to install a transmission pan drain bolt on my Chevy, Mercedes came with one.

Since I am not able to change the fluid from the torque converter on my non-Mercedes vehicles, I change the trans fluid every 15K miles and change the fluid and filter every 30K miles. This is overkill but I consider it cheap insurance since I tend to keep my vehicles until they are ready for the bone yard.

Dale, the 98 E320 is a very nice riding car but I feel Mercedes got carried away with the use of plastic parts. Your 95 E320 is built more like the traditional Mercedes thinking - Quality first, price second which gives it that built like a German Tank feeling.

I believe that the dipstick tool is that long because it is used on various models and they don't want you to leave the dipstick in the "permanent fill" transmissions. The black part at the end of the dipstick is the part that actually measures the fluid level, the long cable is there to attach the black part.

The part number for the magnet is 2202710098 and cost me $3.28 from my Mercedes dealer.

BTW, I also changed my spark plugs (put anti-seeze compound on the threads and dielictric grease on the ceramic portion of the spark plug to make removal easier) and power steering fluid. My hands are a little scraped up but my car has a clean bill of health.

[daddiojiggy]

how did you install the magnet card?did you just lay it on the pan or did you stick it to the inside.i know it's a magnet but you said it wasn't a strong one.is there no chance of it moving around and blocking the filter?

[Southern]

Just lay it on the inside bottom of the pan. The magnet is strong enough to bond to the metal pan without moving around but not strong enough to interfear with sensors.

[Kestas]

RJ, The 7.3 liters you drained from the transmission.... what percentage of total transmission fluid does that represent?

On other cars, I use the technique of disconnecting a line and pumping the fluid out by starting the car, while at the same time refilling with new fluid, stopping when the fresh fluid starts coming out. This gets most of the fluid changed over the "drop-the-pan-and-refill" technique.

It seems this technique I use would be unnecessary if most of the fluid is changed in the 722 transmission by just dropping the pan.

[joe p]

the .6 still has a converter drain ya'll.

get that one too. :-)



Joe

[Southern]

Kestas,

I'm not certain but I believe that the 722.6 holds 8 Liters. Since I pulled the transmission pan plug and the torque converter plug, I suspect that the only fluid that didn't get drained is the fluid in the lines to the transmission cooler.

At $10.50/Liter the "disconnecting the line" technique can get expensive. Also with the "disconnecting the line" technique the trans filter doesn't get changed or the bottom of the trans pan doesn't get cleaned.

I agree that with the "disconnecting the line" technique you change out more of the old fluid but either technique is better than not changing the fluid at all.

[Kestas]

$10.50 a liter!! What fluid is specified for your transmission? Mine requires Dexron III ($1.15 per quart).

It sounds like you get at least 90% fluid change in your transmission. I wouldn't recommend using the flush system I described.... probably wouldn't do any better. I use the flush system on other cars only after a filter change and only because dropping-the-pan method exchanges no more than 30-40% of the fluid.

[blackmercedes]

Originally posted by Kestas
$10.50 a liter!! What fluid is specified for your transmission? Mine requires Dexron III ($1.15 per quart).

The 722.6 five speed fully electronic transmission found in all 1997+ Mercedes models requires an MB specific synthetic transmission fluid that is quite expensive. To all owners of those transmissions, don't put "regular" fluid in them.