treiberg

After reading many posts in this forum, I am a little nervous about changing the tranny fluid on this 1992 300E with 91K on it. I just bought the car and have none of the service records, so do not know if it has ever been changed. Some folks are saying changing it this late in the game can cause more problems, while others disagree. Is there any consensus out there among the "experts" based on more recent information?

Also, if I do change it, what should I use, standard Dexron III or synthetic? Reading through old posts, I get no consistent opinion on this either.

I am hoping some knowledgeable folks can speak on this topic and put this one to rest for good...

rivcal4life

I also have read the myths about changing it doing more harm than good. Simply not true through my own experience.

I found actual particles and almost chunks of metal in my drain pan. None of which would have been better off left inside the tranny.

Dexron III is the only transmission fluid you should use in these automatic transmissions. Thats what they were designed to use. Good luck too man. Let us know how it goes should you decide to go through with it.

berti_00

i changed my oil mmm maybe 1500 miles ago i think... DEX III drained it all... cleaned the pan nicely and put back together and added oil again... nice and smooth....
just make sure you don't over fill

2PHAST

In all my transmissions, I run Redline High Temp Syn. Meets or exceeds all manufactures recommendations.

rivcal4life

From my experience, I recommend royal purple. I have however heard some people experience problems with it and have since switched to redline as 2phast says.

But, I can not suggest them through personal experience.

TheGerman

Just use ATF by DB 236.6/236.7 in your gearbox. It is like ATF Dexron IID.

Everythink else is false.
For right shifting, you need exactly the right ATF. And this is not ATF I oder ATF III, it is IID.

Don't care, this is yust bull****.

There is dirt from your break band inside your gearbox and this is like grinding paste. This will destroy your hole gearbox, if you don't change the oil every 40.000 Miles.

Smedley

When you do it, and find your pan clean, its a good ideal to cut open your old filter to see what a good job it is doing.

Did mine, which has 178k, the pan was very clean, had 40k on last fluid change, the filter under 20power microscope showed very small silver metal chips and some fiber from the clutch packs. This is normal far s I know.

Still shift good with no flair.

Good luck.

rusher

FULL ACK

For very cold regions you can use ATF II E (synthetic) - but generally ATF II D !

ohlord

unlike the 722.6 and .9 that need mb spec fluid.You can use atf3 or backwards compatible atf4.Work safe and work clean.If your torque converter has a drain plug drain it.
www.autohausaz.com
has the filter and gasket set,about $15 use it.

rusher

if you want to wreck your tranny faster you can use of course ATF III...

if you want max life you gonna use ATF II D

Quicksilver500

MB uses regular Dex III so just use that, if you switch fluid this late in the game you can strip the clutch material off the clutches, I know, I did it. You should flush it every 30K and it can't hurt it. When you get it rebuilt use something of better quality and synth 722.6 fluid is good...but for now just keep using whats already in it which is probably Dextron III. Drain the pain, take it off, clean it, replace the filter, make sure you get the old seals from the old filter off the valve body, put it all back together. The tq spec on the pan bolts is like 12-14nm, don't over torque! and tighten in a "star pattern", if you over torque the bolts you will bend the pan and it will leak, they are like 50$. Make sure to drain the torque converter too. Put like 3 or 4 quarts in, turn the car on and shift between the gears to get it circulating then you put enough to make 7qts and then top it off as necessary. If you put all 7-8 in at once the tranny will think its over filled and blow out of the top. Good luck, its really easy. You need a 5mm allen, 13mm socket, a big screwdriver (to rotate the tq converter), and a philips head screw driver.

-Mike

TheGerman

"You can use atf3 or backwards compatible atf4."

It is not backwards compatible.
Not in MB-Gearboxes.

ATF III has a higher liquidness than ATF IID.
It will change your gearboxaction, strongly.
It can also cause brake bands slipp and can burn'em up.

The gearboxes are hydraulically operated without computer operation.
They need the 100% specific oil for the right action on the right time, with the right liquidness, comprehensive restistence, friction coefficent and that all at different defined temperatures.

Good drivers will be able to notice also differences between ATF IIDs with same standards but different producers.

But most drivers don't feel anything and have no idea how good and soft this old gearboxes can work.

TheGerman

And i'm giving a **** of what mercedes benz is selling at the moment.
They don't care about over 15 years old cars and if somebody noticed that ATFIII will work, they stop selling ATF IID and will just maximize their profits.

They were not able to deliver the right oil for my differntial cause they replaced it by a wrong one for differentials without limited slip. I wouldn't wonder if they are also selling wrong ATF Oil.

There are also some kinds of ATF IID on the market without a mercedes benz deklaration. The right deklaration is MB 236.6 / 236.7
The .6 is a little bit more softly. I'am using it from Valvoline.

rusher

TheGerman, you are 101% right!

The most important fact, I think is:

ATF III has more softeners - this softeners corrode the brake bands etc.
And that can be very expensive...


Same thing is with the olders MB, which need ATF I.
If you fill in ATFIII or newer... That will be big problem.

treiberg

OK, tonight I finally got around to changing the ATF fluid. Took 3 hours to do the job, being especially careful at every step. It shouldn't take that long, but I really took my time, to make sure everything was perfectly clean, and being very careful in the refilling process.

OK...the good news...the car shifts so much better now, much smoother.

The bad news...although reverse engages just fine, I am getting a noise now for a few seconds when shifting into reverse that literally sounds like a whistle. it is not a noise that I heard before. I am sure that this is not good, but not sure what else I can do at this point.

Any advice? Anyone ever heard a whistle noise when first switching into a gear? Kind of disaapointed....

TheGerman

Just do nothing.

Real1shepherd

So....what would be your opinion if I found a synthetic product (like Amsoil), that had the MB 236.6 / 236.7 code rating? I understand the transmission is made to work exclusively with ATF IID, but synthetic oils, especially in transmissions, transaxles and differentials, beat mineral oil based fluids in every way. I'm not trying to reinvent the wheel here, but wondering if a synthetic fluid can rightfully substitute for a mineral ATF IID without doing 'harm' to that expensive MB tranny?

Kevin

rusher

The gearbox is designed to run with ATFIIE (synthetic) too.
But you can use it only in very cold regions - due to other viscosity specifications.

TheGerman

If it has the right rating, it should work.
But you don't need to reinvent the wheel, you right, the normal ATF is more you ever need.

This is right, but it can not work in ATMs. In other things, they have a better lubrication with less friction, but in ATMs, you need an oil with a defined friction and you cant't use a better one, elseif the breakbands would not be able to work.

Real1shepherd

My thinking is this; the synthetic will last a lot longer if not indefinitely, given of course, the usual filter change. I think the key thing here is the viscosity of the original oil design. Viscosity in this case = design friction parameters for the bands. That's what the brake bands are designed around and I totally agree, that if you change that parameter, you're asking for trouble. If the viscosity is correct to spec however, I think the superior lubricity, low breakdown and sheer strength of the a good synthetic would have a clear advantage.

That's what I meant about not "reinventing the wheel"....I don't want to spend the money on a good synthetic if there is a chance it will do harm. That's why I commented about staying with the MB spec for sure. I've got 218K on my tranny.....no troubles so far, but I'm looking to extend its life even further. Some would say, "Let sleeping dogs lie", but I don't ascribe to that credo, as I want the best fluid in there I can afford (to extend its life). I'm not afraid to try new things, but I want any change thought out very thoroughly.

Kevin

treiberg

An update:

Just yesterday (about 200 miles after tranny fluid change), I am driving and tranmission slips in a big way, probably when shifting between gears because I think I was going about 20 MPH when it happened (High RPM's, no engagement). I pull over because it just will not engage, check the fluid (which is OK), and then I get back in and drive several miles to the house with no further problems. Reverse always engages fine, but I do hear a bit of a whine when in reverse.

I have read of potential lower $ fixes that work for some problems: B2 piston, vacuum actuator, bowden cable adjustment, etc. Based on my symptoms, do you think it could be one of these, or anything short of a rebuild? I am really hoping so. I am thinking that since this transmission has less than 100K miles, there is a good chance the whole tranny is not shot (hoping!).

Thanks for any help you can provide.

overboostTSI

About 7 years ago the transmission on my 300e was slipping usually after I would get off the highway. So I took a chance (had nothing to lose) and changed the fluid in the torque converter and trans. Car was running fine til about 2 years ago when I started having problems again. This time I changed the filter and fluid. Car is still driving on the same transmission. I used regular off the shelf Dexron as a matter of fact I recall using Murray's crap and the car runs fine. The 300e is not a racecar! You don't need to waste money on special fluids! Try changing your fluid, if your tranny is going out anyway then you have nothing to lose.

treiberg

Yeah, that was what this whole thread was about (see above that I just did the fluid and filter change). But maybe like yours, I can get by for quite a while before having to do anything. I just drove yesterday for several miles with no incident. But it just makes you hesitate to drive to far from ome when you are unsure of your transmission - would feel better if I could have some confidence in it.

rusher

ATF change is recommended every 35k miles - that's what MB says!

Mr. Stanley

My ex borrowed my 89 300ce... Took it to jiffy lube, last week... They "topped - Off" the tranny fluid... The next day I totally lost reverse!