You are trying to walk a pretty fine line there Larry...

If cleaning the varnish out of the valve body also causes the clutches to come apart due to taking out the magic sealing varnish..

Then the transmission needed rebuilding.....

Come on, let's show a little common sense here. You can't flush one without flushing the other. If flushing risks losing the clutch surfaces which necessitates rebuild, this is a no brainer decision. You don't flush it. It's as simple as that.

Why would anyone risk a total rebuild so that the valve body works a little better? Is it better to have a transmission that is not shifting perfectly or to have a transmission that will not move the car at all? Seems like a very simple decision to me.

Happy New Year,

" has its clutch surfaces basically held together with the crud. "

I just do not believe this......

If that is true then do you have some place others can buy " crud" to put into their transmissions to keep their clutch surfaces working longer ?

It does not take but one happenstance of something having occured AT ABOUT THE SAME TIME as another thing for stories to get started about them being related...

When in fact many things happen temporally close together IN WHICH THERE IS NO CAUSAL RELATIONSHIP....

Do you have any Empirical references/data/tests to support the above statement...?

This is the reason Science is not based on ANECDOTAL stories... that controlled comparison tests are used to come up with good advise...
---------------------------------
I am not suggesting ' flushing' in the sense of using clean self powered fluid washing.. but just Trans-X and then draining and refilling... for the record....

Guys,

This is becoming an ominous thread. The originator reported by cleaning his transmission with an admittedly unique procedure that his transmission began working better. The major objections I heard from those responding was that he wasted a lot of automatic transmission fluid. From all the stories about how difficult the resealing of the pan is on these transmissions, and the fatal to the transmission consequences if it should actually leak at a significant rate while you are driving, say, 600 miles on a single tank of Diesel, make this odd approach possibly more interesting. This is how I service my power steering systems - basically a drain and fill operation that continues until the fluid coming back from the system looks like it came out of the can - and it works there, and if I am using an extra quart of fluid than is absolutely necessary, I don't care, my steering stay tight and that is the point. So, stevelewis may waste transmission fluid, and his procedure never addresses the filter (which I do change in the power steering analogy whenever I change the fluid, about every two years) but it is better than doing nothing, which is, strangely, what the W210 vintage and later transmissions require according to MB (and if you elect to change that fluid, you won't waste a gallon or two of it on purpose as it is very expensive).

The debate this has spawned about what happens when a machine with failed parts operates seemingly ok for unexplained reasons and then fails completely when someone services it is interesting but will likely never conclude. If something is working for reasons other than the way it was designed to work, it was actually broken regardless if it was "working" or not. The servicing, which would normally be considered beneficial for a machine operating as designed, cannot be "blamed" for the failure that was previously not apparent even if they occur in seeming sequence.

Engineers design things to work a certain way. It is wonderful if the design and then the manufacturing procedures result in a machine that can still perform some functions when some items are failing or have failed. These are not operating conditions included in the design as no machines are designed to include unnecessary parts that can just wear out or break without any consequence. There are many reasons for this lack of extra junk in machines, but the most prominent one is that these items always add cost (and mass) which are detrimental to sales. And sales are the reason the engineers got the task to design the machine in the first place.

Dirt, varnish, burned transmission fluid by products and other foriegn materials are not included when the transmission is built at the factory, and any transmission relying on the accumulation of these foriegn materials in strategically important locations to operate is already broken. If it is operating it is about to expire and any number of events can occur to bring about its demise. Servicing the transmission in a way that is beneficial to a machine operating the way it is designed may disrupt such chance arrangements of random junk necessary for the failed transmission to work, but so could a pothole encountered at just the right speed and angle, a very hot day, shaking at start up, or just plain gravity over time, and so on.

In the end this subject is not worth a big argument. Machines like automatic transmissions shouldn't exist in the first place. So who cares how they fail, right? Good luck, 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)

Which is why I want a reasonably simple way to put a manual trans in my 300D. It would then very quickly become a *perfect for me* car.

My only other option is "downgrading" to a 240d.. And it would actually be cheaper to do that than replace the trans in mine, as it will need at some unknown point.

Personaly I'm going to continue to change fluid and filter, and am in the process of running with a quart of trans-x in there for a few weeks. Just on principle, or out of spite, whichever way you want to look at it.

__________________
One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

WoW, thanks Jim, thats pretty clear. steve

Yep, this is why I drive manual transmissions as well.

Go to any auto transmission shop or dealer, talk to the guys in the service department and I can promise you that they will back up what I'm saying about flushing a transmission with burned fluid. No anecdotes here, just plain old experience in the shop.

Happy New Year,

Larry, If I go into a transmission shop I would be talking to people with a vested interest in OTHERS not keeping their transmissions clean and in good shape...
They have a vested interest .... MONEY... even if they think they are being honest.. their memory can be affected by the fact that they will make more money from neglect of transmissions than good preventative maintenance....

AND,

They do not get a representative sample of transmission examples to work with ... people bring them a skewed sample...transmissions which are giving them problems... and with too few " N " in statistical terms ( number that each shop or each man can be assured meets the criteria which we are discussing ).. to make an informed decision as far as policy...

And the fact is that ALL of the opinions which I got from those peope would in fact be ANECDOTES.. by definition... not a controlled study of the situation...

Yeah, I'm sure that you're correct. It's certainly a conspiracy theory. All the transmission shops and dealer service departments are run by aliens.

I'm just not smart enough to figure it out. Thanks for the help.

Happy New Year,

It's well known in the auto mechanic business that an automatic tranny "not working right" is a bad candidate for a fluid change. Quite often, it's ONLY working because the fluid is bad and its crapped up -- the shifting symptoms are from sticky spool valves. Nice flush and clean fluid is definitely a crapshoot -- quite often the tranny fails very quickly when the varnish and scorched friction material washes off -- there is then NOTHING on the frictions and it won't move.

Standard frictions are high density paper, by the way -- this is why water in the tranny fluid means instant death, the paper "melts" pretty fast.

Best advice I've heard on automatics (refering mostly to GM turbo 350/400s) is to use semimetallic frictions instead of standard ones. Much longer life, impervious to water, much less damage from slip (they won't char), but do shift harder.

If the tranny works better, hey! Change the fluid every 30,000 miles like you are supposed to, and it may last forever (not really, the frictions eventually die).

When it does, though, it ain't gonna bet a quick set of clutch paks and seals repair, though -- usually by then there is serious mechanical wear too.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Great synopsis JimSmith.

I had an old 220D transmission fail about 1,000 miles AFTER I changed the very old and very cruddy transmission fluid after I purchased it. Its not hard for me to believe that new fluid dislodged old varnish deposits and these deposits pluged up something in the valve body that controls the shifting process that lead to "failure". I agree with Jim that this is not the fault of the transmission - rather its a case of prior neglect coming to light after the recommended service procedures are performed - maybe for the first time ever.

All my current cars get 30K fluid and filter replacements - they do because I've had them for 100K miles and I know the fluid is in good shape.

If I acquired a 230K car that had crappy fluid I would NOT change it - I'd drive it until the trans failed, rebuild it and then begin changing fluid and filters on schedule.

Tim

Thanks Peter. I was being accused of spreading "anecdotes."

So maybe it's not a conspiracy by the auto repair industry after all.

Happy New Year,