722.6 Shift Quality Problems
 

Hi All -

I'm curious what is the collective experience with getting the dealer to resolve shift quality problems on the 722.6 transmission?

Here is the background. I have a 2001 E320 wagon. A few days ago I noticed the 3-4 and 4-5 shifts were not right. Rather than smooth and seamless, they had more of a pause-lurch character to them. This happens intermittently, and seems to require the transmission be very well warmed up - it first occurred on a 300 mile drive home from spring break holiday. The problem is subtle - the car is not barking the tires here - but definately not right either.

The car is still under Starmark - for 4 more weeks. I dropped it at the dealer this A.M. for diagnosis. What should I expect them to do? What if they come back with No Problem Found? I'm concerned they will return it without doing anything, and when I have major problems in 2 months, or 6 months, it won't be under Starmark. Thoughts?

- JimY

Specifically have them check the plug from the electrical harness to the transmission. Even the slightest amount of fluid on that connection can cause a variety of problems.

Using SDS they can look at the adaptation values and see what the trans is doing internally during those shifts.

At very least, be sure that you have paperwork with the compaint specifics from the dealer. Take it in two or three times under warranty, it should give you what you need to show that the problem existed under warranty. Documents, documents, documents.

That's pretty much why I took it in today. I don't expect they will be able to experience the problem; the car needs to be fully warm and even then it's a bit intermittent. Maybe SDS will show something awry - assuming they look at adaptation numbers and don't just look for error codes.

Problem with the shotgun approach is they charge a ~$100 diagnostic fee if they don't find a problem covered by Starmark.

Reading old posts, seems there's a good chance it's just a little low on fluid. I'm hoping they check that - I don't have the dipstick tool. Nothing on the garage floor, but I haven't been under the car either. Trans has never been serviced; dealer says MBUSA never issued updated maintenance schedule and refuses to perform routine servicing on it. Seems to agree with what I've read in the archives; many countries changed to require servicing at ~40K miles, but not USA.

- JimY

Not correct; MBDOC has posted the docs previously. IIRC W210's wern't on the list as they were out of production when the doc was issued.

just to add my little bit of useless knowledge - but I find these cars need a GOOD battery, or else funky electrical issues occur - and these transmission are computerized electrical gizmos.
I had trans issues on my 2002 C-class, and it was due to a five year old battery that wasn't used often.

I'm searching old posts but not finding that. See this thread in which Mr. ILUVLMILS states that a single transmission service was added to the 2006MY cars at 39K miles, but does not appear on the service sheet for earlier model year cars. See post #5: http://www.peachparts.com/shopforum/showthread.php?p=924260

There is also Gilly's infamous "we didn't say who's life" document, see post #8 here: http://www.peachparts.com/shopforum/showthread.php?p=702285#post702285 But again, no general service interval is set for the 722.6.

Can anyone find anything different?

BTW, the car has a 1 year old battery, so funky electrical problems it isn't.

- JimY

See #41 & 45. http://www.peachparts.com/shopforum/showthread.php?t=222123&page=3

I might have the doc saved at home. As I recall it did not inlcude W210's specifically as they were not in production at the time.

OK, that's it then. Looks like the omission of the 210 chassis was a typo, nothing more. It's interesting to note the main focus of the SI seems to be preserving shift quality, not transmission life. Thanks for pointing this out.

So, how annoyed do service advisors get when you point stuff like this out to them? :)

- JimY

In hindsight, rather than a typo, I suspect it had to do with the fact that at the time the doc was written the W210 had ceased production and had already been replaced by the W211.

As a followup, I finally serviced the transmission a few weeks ago. I used the Fuchs 3353 (I think...bad memory) fluid. With no torque converter drain plug on the 2001, I instead disconnected the trans cooler fitting at the lower/center of the radiator. The transmission was kind enought to pump out surprisingly close to all the old fluid though the dangling flexible hose. I bougth an extra liter or 2 to permit flushing out the old stuff.

Dropped the pan to change the filter. It was shockingly clean. After 70K with no service, the pan was absolutely spotless. There was no debris whatsoever.

Took it for a drive, and wow! Much improved. Even the gear changes that were fine before are better now. The 3-4 and 4-5 that were the basis of my original complaint are greatly better, but not quite seamless. After a few hundred miles it seems the trans is adapting and things continue to improve.

Highly recommended service.

jcyuhn,

Is the procedure, unhook line, turn on car and wait until the majority of old fluid is pumped out?

That's the way I do it on my old Lexus but I've never seen it suggested for the 722.6. That would be the only way for the DIYer to get a complete fluid change.

thanks,

glenmore
1991 300CE
2000 C280

I'd like to know the answer too. How long can the tranny be operated dry without causing damage? I plan to service the 722.6 in my 1997 E320 and from everything I read it doesn't look like I have a torque converter drain plug.

The 1997 has a torque converter drain plug. For 722.6 up to model year 99, there is a spring (Pressure Control Valve Spring) that tends to collapse or break. When that happens, the up-shifts will be rough, especially 2 -> 3 and 3 -> 4. So when you change fluid, definitely check that spring and it only costs $2. See the diagram.

For jcyhun, the design changed but the spring could still experience problem, therefore affecting shifting quality. It is too late to check now because the oil pan has to come off.

I recently had to replace the conductor plate on my 1997 E320 and bought several of these springs just in case when I had the valve body out of the car. Mine did not break but was collapsed.