722.6 Fluid change and misc items...
 

Wanted to post this information here for anybody who has a 722.6 transmission.
This is related to the 2002 CLK320.

No torque convertor drain plug on the CLK unfortunately. Plan is to disconnect line at transmission cooler near radiator and have it go into an already marked 2Qt bucket.

First I will drain the pan, clean it thoroughly (I expect a horrible pan @ 105k original fluid (i think)), replace filter, refill with fresh new fluid the same amount of fluid I drained. Start the car and let 2QT flow into the bucket. Turn engine off, top up 2QT, and repeat until the fluid comes out as clear red as it gets. I have bought a total of 12QT's of fluid for this.

Do NOT use Valvoline Maxlife, it is not MB approved and if you search, there are plenty of threads on this at other forums. Its "compliant", but not approved by MB. The original fluid is Dex III-based, but a variant of it due to the electrical components inside the transmission and there have been no long-term threads who users have Maxlife have reported back anything more than 40k worth of history using it. The 722.6 has proved itself in taxi's of doing almost a million km's with nothing more than fluid changes every ~50k miles. I wouldn't want to risk it saving $20 on a change since the Shell 134 is only $2 more a quart.
You can purchase Shell 134 MB approved fluid at Ryder Fleet Services for $5.5/qt online. No reason not to use this.

http://www.w124-zone.com/downloads/p...s/shell134.jpg
http://www.w124-zone.com/downloads/p.../shell1342.jpg

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While under the car, I plan to replace the transmission plug/adapter that is known to leak or force fluid up into the module in the engine bay causing erratic shifting and other issues. Luckily its not damaging since transmission fluid is non-conductive, but it does require you to pull everything out, clean it and drain transmission fluid etc....I decided to be pro-active on this.

DO NOT buy the adapter @ the dealer!!! Go to a local Dodge/Chrysler dealer and they have the EXACT same part that is used in the Crossfire, for half or a third of the MB price. I paid $10 for it. Even comes in the same box!!

Will post on Saturday with more photos of fluid change and results.

http://www.w124-zone.com/downloads/p...226adapter.jpg

OTOH we had a owner with a E300D with the 722.6 who was a travelling salesman, put over 300K (in the course of only a few years, normal for this guy)on it without ever servicing the transmission. He traded it on on an ML and a service writer at the dealership bought it, continued to drive it over 50,000 additional miles, he then went to a different dealer so I lost track of the car. Trans was never serviced.
I therefore have the opinion that either your trans is a good one and will last or it will bite the dust earlier than this, regardless of if the oil is changed. My opinion ONLY on the 722.6, if it is an earlier trans it should be serviced according to the service schedule.
The color of the oil has nothing to do with the quality of the oil, it turns black due to graphite friction discs, it is fine even when black.

I just cannot comprehend any logical argument why changing the oil would have a detrimental effect on the longevity of the transmission, on ANY model unless it was replaced with non-approved fluid.

If the fluid turns black because it is carrying graphite in it, that cannot be good to circulate around all the components for a long period of time...
I'll be getting my Blackstone fluid analysis back by weeks end, so we will see what the actual labs say about the "so-called" lifetime fill fluid.

MB wouldn't have changed their opinions from lifetime back to 39k intervals if there was not a good reason...

My girlfriends old 2006 Audi TT had the lifetime fill garbage...transmission was trash at 70k miles.

This is all great info! BTW, where is this plug? I've looked around for it and don't see it (2000 C280).


Thanks

Here's the guide I am using:

My attempt at replacing the transmission plug. - Benzworld.org - Mercedes-Benz Discussion Forum

Seems it is hidden behind a shield. A few posts down you can see his photos of what happens when the seal breaks and the fluid works its way up to the module. Looks messy!

Indeed, but the reason may have been that they needed to cover for a piece of crap transmission. The ZF six speeds seem to be doing fine with lifetime or long interval fluid changes. Land Rover is 10 year / 150k interval and you rarely see a transmission problem on a Land Rover forum. The 722.6 is just a piece of crap by comparison and the .9 is even worse.

Interesting that Sun Valley is allowing Dexron III on 722.6s if changed every 24k miles. Those guys are no dummies. There was one post a while back from someone who had used WalMart Dexron III in a 722.6 for a couple hundred thousand miles without a problem, with regular changes.

The policy at my dealership is simple. We won't service any transmission if the vehicle has over 100,000 miles unless the transmission has been serviced previously. This policy has been in place for several years.

Prior to this, we had occasional transmission failures shortly after routine service was performed.

My neighbor is a technician / Team Leader at the local Mercedes dealer (Penske), and he says the 722.6 is the most bullet proof transmission MB ever built (from 2000-on).

He says he never sees a failure.

In fact, when MB went to the 6 speed transmission in the 211 chassis, they kept using the 722.6 in the AMG models because the 722.6 can handle the torque.

In fact, the Mercedes / McLaren SLR uses the 722.6.

I've had techs tell me it was the worst they ever built (until the .9 surpassed it). I've always thought it was a candidate for the worst transmission ever built by anyone. There have multiple stories on forums over the years of individuals dealerships having done overhauls/major work on over 5,000 of them - at a single dealership, and that was years ago. No doubt it got better over the years but the 722.6 was a major blow to Mercedes' reputation, right up there with wiring harness and ASR.

So far so good for my 722.6, 2000 C280 with about 96m.

I had a new tranny put in my 1991 300CE at Sun Valley.

He said the newer trannies coming in that did not have fluid changes, i.e. lifetime fill 722.6s, were coming in thrashed. He said the innards looked like they had been sandblasted. He expected even worse from the latest trannies because electronic parts sit submerged in the hot oil. Could be just counter banter.

He said just change fluid regularly and no need for the fancy stuff.

Looks like we are in the clear for coolant!
That's a big relief that the Valeo radiator that was in there for 100k was safe. I think we are golden going forward.

http://www.w124-zone.com/downloads/p...nsanalysis.jpg

I have heard from several friends who work on MBs (dealer techs, indy shops), and they all say the 722.6 is bulletproof.

Met a guy in SoCal with an 03 E55 thats got 200k miles.... Hes been running a pulley, headers, tune, and modded cooling system for 90k miles, making about 525RWHP/600RWTQ.... And the transmission has yet to give out.


The car has made quite a few 10 second passes with drag slicks!

Since at the time you wrote this I was the only one who had posted, I will assume you are referring to my post.

What I am saying is NOT what you are suggesting, that it would be detrimental to change the fluid.

What I am suggesting that it is not detrimental NOR beneficial, there is a difference. Change it if you want, but it's my belief that it is more or less a matter of fate, it depends on how close the tolerances are on a particular unit.

Here is a post I've copied a link to on different threads, keep in mind that for the most part (except my added comments), it is straight from Mercedes:
http://www.peachparts.com/shopforum/702285-post8.html

That's a nice thread. I still can't believe someone at Mercedes said "we never specified who's life." They didn't just say it, they actually wrote it. Crazy.

That's also the thread in which MBDoc says (in 2004) that his dealership has replaced/repaired 2,000 722.6s in the last 2 years alone, at a single dealership. That's a colossal, epidemic failure by any standards, not what I would call "bulletproof".

I'm seeing the same thing with the lifetime fill BMW transmissions.