There is not a hell of a lot to go wrong. I'll be happy when we understand the failure mode.

 

There was an ask pump failure analysis, and I happened across this thread about a pump failure started by a mb tech: http://www.benzworld.org/forums/gene...nsmission.html

Quote: "found the trans pump was not working as no fluid was coming out of the lines. anyway i took apart the trans to find the pump has broke apart, the bushing seized to the torque converter and the pump had caused damage to the bell housing."

Sounds like a bushing failure? I bet the poster of that thread might be able to shed some light on the issue.

 

Bush/bearing - we are speaking the same language. I'm almost sure that the bush/bearing is the first point of failure. In the cases we have seen on MBWorld – 4 that I know of going back to CPBeasley’s thread, the pump has not stopped pumping. The transmission has operated "normally" with that awful TC whine in the sound clips when revved. The AMG SLK55 that I know of here that suffered this failure began by whining on start up until the oil pressure in the transmission came up & then was silent. It was repaired before this progressed.

Some enlightenment. I phoned my old service manager pal Stanley who moved to Bentley & now owns his own Benz shop. He confirms that in SA we have only seen this failure on AMG models that have been hammered & not serviced & the fluid has been in SHOCKING condition - heavily oxidised & with clutch debris present. He feels that the very few he has seen were probably due to bearing/bush failure because they were repairable with TC, shaft, bearing & seal replacement. He has not had to replace a pump yet. He has never seen this failure on a standard non AMG model.

Now this gets me thinking - SA consumes 2/3rds the number of Benz cars every year that the US does so it is certainly a representative sample. It would be interesting to see whether there is any correlation between failures & Aluminium pumps vs. Steel pumps. However the big difference between the US & SA is that Benz cars here are sold with a 6 year 120,000Km Mobilodrive maintenance plan which is extendable for a further 2 years for US$ 875 to 8 years. So all normal cars in SA get their regular 60K Km (39K miles) transmission services as part of the maintenance plan & at the insistence of MBSA. Further to this in SA where Benz cars are expensive & maintain their value, people continue to service them at dealerships to get the stamp in the maintenance booklet because it helps maintain value for resale. (e.g. I got US$ 22,000 for my 8 year old C240 even though the Rand has slipped from 6.7 to 8 to the US$)

I postulate that MBUSA has shot itself in the foot with it's filled for life BS & later change once at 39K miles & now it's chickens are coming home to roost & it is sitting on a time bomb. There are many 722.9 equipped cars in SA with 500,000Km plus on them with no issues.

Further - If I had an enthusiastically driven AMG with a 722.9 I would reduce the transmission service interval as one would generally do on a high performance vehicle.

For the rest of us members, while we investigate this issue I really can't stress sufficiently that you have your 722.9 serviced EVERY 39K miles as in ROW. Please ignore the change once instruction. This is an expensive transmission to repair even in the US.

jfelten - thank you for posting.

 

Thank god my car doesn't sound like that sound clip Doesn't get louder when I rev higher either However, I am playing russian roulette right now Only when I am sitting idle do I here a low whining sound. Ordering some transmission fluid, gasket and filter as I type this. Madd scary

 

Pleased to hear that. Excellent news!

 

I am thinking it's the poly v belt that needs replacing.

 

MBUSA has more than likely not shot itself in the foot.. rather, shot everyone who bought one of these in the face. The W203s are all out of warranty now due to being time expired. So if you bought one and followed MBUSA's maintenance plan of changing it once at 39k, you could be in for a gigantic repair bill literally in the thousands of dollars maybe even before 100k. Alex's repair is costing literally half the value of the car. That would be completely unacceptable.

 

Glyn,
Is there a way to check tranny fluid level yourself? I flushed mine in the 05 CLK55 but I think I have a small leak so I'd like to make sure its at the right level. Sometimes it shifts a little rough till it warms up.

If I grabbed a dipstick from another car any idea how far down should I insert it?

 

The 722.9 has no dipstick tube. You have to get the temperature correct & set level by the spill over method. See 722.9 service sticky at the top of the W209 forum & top up with a syringe.

 

Indeed - however Americans are known to be litigatious & I guess a class action may loom although I'm not convinced they are all that successful.

I think the W204 & others might bite MBUSA.

 

It was successful against Honda. They ended up having to extend the warranty to 7/100k on all of the vehicles affected. But in that situation now the market is full of Hondas that no one in their right mind should buy even though the bodies, interiors, and engines have tons of life left. I'd hate to see the late 203s and the W204s fall into that same category where no one wants to buy them used and out of warranty. Perhaps, though, Mercedes can actually fix the problem unlike Honda where it was an inherent design flaw that couldn't actually be repaired.

 

Since some of you obviously know a thing or two about these transmissions let me ask a question. 2008 CLK 550 with 36,000 miles. Not driven hard. Under warranty until mid-April. A couple months ago I noticed that when cold it had a rough shift between I think 2nd and 3rd. Only that one shift. By rough I mean that it would feel like it bogged down for a second - like it wanted to shift but could not, then would shift suddenly. No noises or mechnical sound. It varied quite a bit in how severe it was. Many times just a barely detectable hitch, and other times you'd jerk in your seat a bit and the nose of the car would dive a couple inches. When it warmed up it was pretty much gone - I could just barely detect it - so faint that hardly anybody else driving the car would ever notice. But then after a week or two it mostly went away. By the time I took it in they found nothing wrong - they updated the software, but said all shift points were at the correct time and fluid at correct level. In my head I'm picturing some valve that was sticking when cold, then suddenly releasing a second after it was supposed to, but that it has now freed up. What is the likely cause of what I was experiencing, and is a fluid change likely to keep it at bay? Obviosly what I fear is the post-warranty hole in my wallet. Thanks.

 

Some 722.9 transmissions had to have valve bodies replaced due to rough shifting. A member here KARO had his replaced in his 06 C350 free of charge due to harsh shifts, but his were all on deceleration and not just when cold IIRC. Someone else will need to chime in.

 

Being your car is a 2008, you should have the latest valve body. You are very close to the 39K service required. I would suggest you take it to the dealer have them do a PROPER service, (They need to be reminded to do the service correctly to the new WIS procedures, meaning DRAIN THE TORQUE CONVERTER.), reset adaptations, and torque converter lock adaptations and drive it for a few hundred miles and see how it goes.

I have found the 7G tends to get some weird shifting characteristics when cold as time goes by, and it adapts to lazy driving. The 7G needs to be kicked in the *** on a regular basis to keep it running correctly, IMO. I am also a firm believer in resetting ALL adaptations with a service. There really is that much of a difference in fresh ATF characteristics, that it is essential to have the transmission adapt to the new fluid.

 

+1^

 

I am certainly more than happy to kick it the ***, and I will get a fluid change. But as for the actual cause - it is one of those "who knows" sort of things?

 

When you start these cars from cold they go into high idle & open loop mixture enrichment. At the same time they hold gears for a little longer to warm the Cats more quickly (along with the secondary air pump etc). I think this could be part of the TCU behaviour when sensing low temperature.

As long as there are no strange noises I would change the fluid & drive the thing & see what happens.

You should have a new generation 722.9 & they are supposed to be trouble free if maintained.

The only known problems on older transmissions have been the conductor plate/speed sensor problems & this TC failure mode which is not fully understood yet but I think relates, at least in part to lubrication if the fluid is not changed & is allowed to deteriorate.

 

Agreed. If you were getting these weird shift characteristics when warm, I would be a little concerned. But the warm up cycle along with adaptations will cause some weird shift characteristics. This is considered normal. Every 722.9 equipped car I have driven has had that behavior. Though the new 722.9 plus does not in the one that I drove. I have yet to see a valve body replaced for sticking valves. They are only conductor plate issues and TCU issues on earlier units. I am told all 2008-up have the latest valve body with updated conductor plate, so it should be sorted now on them.

 

Hey guys my car is an 09 c300 4matic sport and my car is at the dealership now because when im driving the car and I accelerate like taking off from a light and I reach between 3000 and 4000 rpm and i decide to stop short to take a turn or for whatever reason it may be, I feel like a (Push/Kick) like the car not downshifting smooth and right now that I have a 2012 c300 4matic loaner it doesn't do that, I drive my car on S mode and the loaner too, do you guys know what could be the problem or what I should tell the mechanic while my car is at the shop now before I pick up? Also does my car have the 722.9 transmission too or which one do I have?

 

It's likely your car still has one of the older transmission software flashes. They used to do that & you could catch out the TC clutch. I'm sure they will load the latest software. With the latest flash the car comes to a halt in 2nd gear as well. You have a 722.9.

 

ALRIGHT!! I GOT MY CAR BACK!!! WOOT!!! My extended warranty covered everything. The total was around $4,500 and the things that needed replacing were the torque convertor and pump. The dealership also replaced all the seals and gaskets too free of charge .
It feels amazing to drive my w203 again but I feel like my tune disappeared or i got too used to smashing that boosted C250 =/
Not sure if they went through my ecu and changed the tune cause the OBDII port inside the car was still open . I will probably have to head back to OE_Tuning to get this checked out.

But anyways! The car does not make any noises now and feels 'newer' haha =)
Many I love you W203 Community! hahaha and most important Glyn for all the technical information and help!

 

Pleased it's sorted & had a pleasant ending.

 

Hey Glyn what is "They used to do that & you could catch out the TC clutch"? and what is "With the latest flash the car comes to a halt in 2nd gear as well"? Also, my mechanic has been very cooperative with me and he told me anything to let him know, so is there a name for the software update or part number or what should I tell him so he can update it for me? Thanks Glyn and sorry for all the questions about this but I just wanna learn more about this transmission situation and get it fix ASAP cause my lease is coming to an end in couple months.

 

OK - let's not get carried away with too much detail. Tell the dealer to make sure your car has the latest TCU flash. If it has tell them to reset all adaptions. They will know what this means. If it has not then they must load the latest software to your TCU.

 

K thanks Glyn I appreciate the help