Ausmbtech

I've been looking into the cause of the C43 transmission failures.

The C43 was fitted with 3 different 722.6 transmissions.

722.602 which is only rated to 330Nm continously. This was also fitted to alot of other smaller engined W202's

722.621 which was only fitted to C43 and early 600's (M120 engine as fitted to W129 and W140) rated at 580Nm continously.

722.631 which was fitted to the C43 only (580Nm rating).

Other transmissions can be retrofitted but these are the factory fit versions.

I know that the early 330Nm rated transmissions had a weak point in the bearing located at the end of the inputshaft where the nose of the output shaft fits. The early 330Nm transmissions had a bush fitted instead of a bearing(580Nm versions got a bearing). The bush wears out and puts greater stress on the input and output shafts causing an eventual failure of the transmission. I have also seen this occur on some C250 turbodiesels (280Nm engine rating) with this transmission.

All current 722.6 transmissions now have a roller bearing, they no longer change bearing design between 330, 580, 780 and 1000nm variants.

What i would like to check with everyone that have had a transmission failure is to check what transmission variant they had when it failed (some may since changed versions).

Hopefully if there is a direct correlation between failures and the 722.602 transmission then the transmission torque rating and bearing design can be put down as major contributing factors.

I still believe that regular oil changes (as your driving style requires) do help extend to life of the transmission.

I have found a failed transmission out of a c43 in the dealership basement (722.602, customer bought a complete new unit), if enough people agree that only the 722.602 is the problem transmission then I'll disassemble it and post pictures of the failure points.

Hope this helps remove some mystery from this issue.

John-in-Dallas

Very interesting post AusMBtech. Thanks for doing the research.

I'll bet I'm not the only one wondering how I tell which of the transmissions is in my car.

Were the transmissions specs a function of date of manufacture? Is there evidence in ID codes on the car? P/N somewhere on the tranny? Thanks.

Ausmbtech

The transmission number can be found by checking it on the side of the transmission near the sump. Only the 722.XXX is required from the entire number. If you still have the data card in the owners manual then it can be found written on it.

If you're near a dealer you can always stop by the parts department and ask to get the data card printed out.

Those that have had a transmission replacement need to find the origninal transmission version, when a dealer fits a new transmission we update the datacard accordingly so that can't be used to find the previous transmission number

KJI3jflarryfe93

hey buddy i checked my trans it has the number 722.631 (580 nm)
does this mean my trans is bulletproof? i change my ATF when needed to! my car is almost 59,000 miles on the clock

How can mercedes put in a weak trans in such a high power car? 722.602 trans!!

the other ones with the end number 621 or 602 are they less durable? meaning they gonna break?

thanx for the input buddy

Ausmbtech

I'm not saying that any particular transmission is flawed or bullit proof. I'm trying to find the common fault of a major failure that just seems to affect the C43 with an otherwise reliable transmission.

I know of 1 failure on a vehicle fitted with a 722.602
I'm looking for all those who have had a transmission failure to post what transmission version was fitted to their vehicle in the hope to help determine if this is the contributing factor to the failures.

John-in-Dallas

Hi Ausmbtech.

I haven't had a transmission failure, but just want to report which trans my '99 C43 has got. It's the 722.631. This is the trans that is shown as standard in the archival data for the cars specifications.

I've only got 39K miles on my car, and I'm hoping that I've got a lot of life left in my trans. Yes, I've had the dealer service the trans and change the fluid. My understanding is that only a fraction of the fluid can be drained (4 quarts out of 12?) without taking the thing apart.

Thanks again for your research in this matter!!

ProjectC55

That is also why I cg my fluid very often!

Ashkan's C43

Any updates with this issue? Would there be anyway to beef up these trannys to handle more power?

Kropf

1999 C43 with 722.631
I bought the car with 94,000 miles.
At 99,783 miles, I drained the transmission and converter (very dark fluid - no burnt smell - no metal pieces sitting in the pan - upon later disassembling the old filter, I found some very small metal slivers in the filter cloth).
I put in a new filter, and refilled with M-B 001989210310 synthetic ATF.
All was fine. With little more than 101,000 miles (about 1,300 miles on the new fluid), I brought the car to a M-B dealer on Monday to get a windshield replaced on Tue. Dealer said they drove the car 2 miles up the road and back Tue morning - nothing abnormal.
Dealer started car this Wed. morning, they put it in reverse, and noticed bad transmission noise. They dropped the A/T pan, and said fluid was very dark, not burnt, but much metal including needle bearings were in the pan.
Dealer wants $7,000 to repair with a M-B remanufactured Transmission, Converter, fluid, and labor - warranted for 2yr, 24,000 miles.

I though the 722.631 was the strong transmission, but certainly doubting it now!

Still checking my options...

svt ricco

how much does the tranny fluid change cost at the dealer? my car is due for service soon. thanks in advance

svt ricco

is this easy?my father in law is a mechanic but he only deals with jap cars

SeeKlasse

Hey... youre in NY? ok so who cares what happened before now you have a broken very expensive transmission... same thing happened to me last week, ive only had my car back for 6 days now with the new tranny in it... i noticed early last week that the car wouldnt accelerate in 4th gear and would hit rev lim if i tried to give it some pep, so i called my mechanic (who is awesome by the way, hes a certified mercedes benz senior mechanic, worked at dealerships before opening his own shop, where i get 120 dollar an hour service for 50 bucks an hour!) mechanic tells me im screwed and need a new tranny. dealership gave me the same kind of quote they gave you, "6500". luckily my mech knows one of the few mercedes certified tranny rebuilders on the east coast (he is the guy who rebuilds them for dealerships when they have people like you and i come in there with broken trannies, they dont rebuild them, they outsource to a certified rebuilder) apparently you have to be a dealership to get his business hes not open to public, but since my mech knew him from dealership days they do business....

he gives the guy a call, who happens to have a 722.631 on hand but needs to be rebuilt before he can pick it up (the rebuilder is in atlanta). anyway so i dropped my car off on tues last week, the guy finishes rebuilding the tranny on thurs, at which time my mechanic, having already taken out my broken trans, takes my core to the rebuilder for a swap. the rebuilder charges him 2900 for the trans, and my mech charges me 50 bucks an hour for the 8 hours of work it takes to swap it out. after taxes im out the door with a new o2 sensor too for some reason totalling up to just shy of 3500.

3500 is a far cry from 7000, especially when its the EXACT SAME REBUILDER. not only is it half the price, the rebuilder (who has never given my mechanic a faulty trans or torque converter (comes with rebuilt tranny)) states "just go ahead and floor it as soon as you get it back, no need to break it in just drive. you have 2 years and 35000 miles to break it at which point ill rebuilt it for free" i felt extreemely reassured when i heard this coming from both my mechanic and the rebuilder so ive been flooring it ever since last friday morning when i picked the car up. its been great no hiccups or any bs like that just smooth up/downshifting and flawless performance especially under full load.

let me know if you want to arrange the purchase of the tranny through this guy, by the way the rebuilder sells these trannies to dealerships for 4900 bucks! all this because he knows what they charge... pretty nice guy charging my mech a mere 2900!

goodluck otherwise, i f'in hate repairing my cars, i only like to drive em... hard

ohlord

$2600 at
http://germantransmissions.com/sc5_mbz.asp
diy for fluid change on 722.6 trans on benzworld.org w210 diy section
special dip stick required me $40 delivered
always clean all lines and replace the tq con when r/r the trans.
ohlord

SeeKlasse

also a great deal... now to find a mech to swap em out for you, unless you have the tools and lift to diy

Ausmbtech

I'm now going to be rebuilding mine even before it faults, i'm finding i'm concentrating of the gearshifts too much when i drive it and not enjoying it (my mind goes into "diagnostic mode").

To replace all clutch linings, all bearings (not normally done during a basic rebuild unless a specific fault is found), both freewheels, electrical plate, toque convertor clutchs replaced (the only thing i can't do myself), it's going to set me back $2000 and 2 days of lost work. If a bearing lets go then it's going to cost me the same PLUS a secondhand gearbox to rebuild (around $6000 in my area).

Cheap piece of mind.
Just got to get the boss to let me use the workshop to do it!

Kropf

Yes, 100 miles north of NY City, 950 north of Atlanta (although I've driven to both many times).

Please PM the info to me.

Kropf

Hum, maybe the Atlanta rebuilder is not available for a NY customer?

Anyone with any experience with either of these?

Phoenix Remanufactured Transmissions
(Busy outfit sells on eBay also. Member of BBB with lots of complaints, but all 'resolved'. Up to 4 year warranty parts/labor/shipping.)

Silver Star Transmission
(Smaller outfit, BBB accredited with no complaints, only 1 yr warranty. "All 722.6 trans include updated (new angle) gear sets and update valve body" "OEM parts" "#1 remanufacturer of M-B trans.")


(It's looking like it's time to put a lift into my 12+ft ceiling garage.)

mis-u-jerr

A 631 checking in, I have had LOTS of problems with mine. In fact, that is what brought me here today. It is acting up again. With no warning (well, a couple of clunky shifts last night but...) left a light to get on the freeway and it wouldn't shift out of first. Then I turned it off & restarted it and it was OK for a minute, then after searching between fourth & fifth it seemed stuck in fourth and the CEL came on. Got home OK. Drove around the block later and it shifted but was still acting funny, searching for gears, etc...

Past history:
Nothing like this has happened before. Took it in under warranty for whiny transmission at 32K and they replaced the sun gear. At 40K took it back in and they "basically rebuilt everything except for the center shaft" according to the tech that worked on it. The transmission was even more whiny after that one but it went out of warranty while they were working on it (had it three weeks) so they wouldn't even look at it after that.
Other than some clunky shifts it hasn't been too bad till now, but I don't really beat on it much at all after the last rebuild.

C43AMG

If you guys are serious about keeping your cars wether to race them or keep them, you might want to check this thread :
https://mbworld.org/forums/showthrea...ansmission+vrp

SeeKlasse

anyone want to buy an almost new tranny with 110 miles on it and 26k miles left on the warranty?

Kropf

Sorry to hear about the crash, but PM sent!

sprins

I'm not sure if I'm going to support the topic starters theory with my experience:

I did a VIN check and my car (MY1999) lists with 722.631 tranny.

From what I know of the history the previous owner had a new tranny installed by warranty after some 75K miles. It could be that they upgraded the tranny from a 'lower' version and updated the datacard, but I cannot imagine they would go through all the trouble of updating the datacard at all.

So I assume it was delivered with 722.631 which had to be replaced at a given time.

Kropf

Well, I certainly disagree that the 722.602 is the only 'problem transmission'!!
The 722.631 in my 1999 C43 built in 07/98 certainly failed (as have others noted in this thread), and in mine at least, the tiny input/output shaft roller bearings are the point of failure! (At least bushings don't usually fall out!!) Here, take a peek: Pic1 Pic2 Pic3 Pic4

SeeKlasse

hey man, sweet pins!

no, really though u guys wanna see a ****ty pic?

Im gonna be parting the car out. im interested in alot of stuff from it to pep up a "beater" c280 to keep the rush hour risks off my next c43.... the rest of the parts are useless to me and then im gonna sell the remainder to potomac auto (who will take the immobile wreck off my hands)

StapleGun

Kropf those pictures of those 'rollers' send shivers up my spine