Hey guys, I have a 2004 SL55 with only 19k miles on it. After getting a run of the mill oil change at the dealer, I've been confronted with various problems. When starting the car, there is a noticeable noise from the engine/transmission that wasn't there before. I took it back to the dealer as well as an independent, and they say it sounds normal. I know my car very well and it is NOT normal. Ever since the oil change, I've also had the transmission slip into neutral while moving under light tranny pressure (going downhill, etc). Shifting is slightly delayed, etc etc.

I've read around here that this could be a software issue... is there a flash available? Noone seems to know the problem around town, so I'm in a crunch and look to the experts on this board who aren't after my wallet!

I hate taking my car in anywhere, since I've been victims of joyrides that I couldn't prove before. ****ing dealerships. How can you mess things up with an oil change?! I can try the poor man's ecu reset, but perhaps there are other more solid options, such as a trans fluid flush or something?

Thanks in advance, fellas.

-Long

the tranny is not a serviceable unit on these cars, so no you cant change the fluid. sorry thats all i got for you

Check fluid level, may be low. And yes you can do a tranny flush and change, I have done 2 times. Fluid was green, crazy. I had that going into neutral after a wot blast. That was torque mgmt to save tranny. Add fluid or change it.

So I've taken the car into 1 dealership as well as 1 independent shop so far. Neither have been able to answer my 2 questions:

1. Why is there a new weird noise from my motor after an oil change?
2. Why is my transmission slipping out of gear randomly?

Found a new independent shop that was highly recommended maybe 3 miles from my house. They are total pros and gave me likely diagnoses of my issues:

1. Sound likely from lifters from use of a lower viscosity oil, so no damage should ensue (whew!)
2. Early model (2003-2004 MY) SL55's have a known issue with the transmission control unit. This has to be replaced through a dealership since it requires programming through their network. I may even qualify to have assistance through MB via the 7 yr emissions warranty or something to that nature. If so, I may be able to get parts paid for and just pay the labor, effectively cutting my out of pocket expenses in half. I'll update on this after I know what's up for sure. OH, and they gave me a 2009 C300 as a loaner... which was the last on their Enterprise lot amongst the usual Impalas and Corollas =)

So, today is a good day. I moved to Cali just 3 months ago and it's always a trial and error process to find an independent shop that you can trust and who know their stuff. I can also more or less have peace of mind that I won't require a transmission rebuild or replacement. After this is all done, I can finally drive without the paranoia of my car slipping into neutral mid-throttle. Hope this helps others that may have the same issues. I will keep you all posted!

p.s. For folks in the Orange Socal area, the independent shop is Hi-Line Mercedes run by Matt Hegwood... who then recommended me to his connection at Fletcher Jones Mercedes in Newport, service writer Steve Bates. Both great people to work with!

Cheers,
-Long

You know that there is a comfort and sport setting right?

Yes, but what is the relevance?

Update:
Changing out the valve body and control unit. Parts are 2400, but MB is paying 50%, so I only have to pay 1200 parts, around 600 labor, with tax, roughly 2,000 bucks. I'm happy and unhappy at the same time.

Lets just hope, thats the solution!

you mean the TCU that is black color in passenger side engine compartment next to ECU or the unit under the shift knob. I used to have that falling into neutral problem, was told it was due to too much torque for trany to handle.

The net is such a crap place to look for real answers. One guy says the trans can't be serviced and the other says it can.

According to mb. it has lifetime tranny fluid, adn there is no drain plug or pan on them. thats just what the dealer said. if its true or not, i dont know

It's the control unit in/on the transmission, so maybe the one under the shifter? I don't know enough about these cars to say for sure, but from what I'm told it's on the actual transmission.

-Long

you need to be kicked off of this forum

EAT A DICK

there is a trans pan on the r230's. You should get the BG tranny flush along with replacing the trans pan and gasket here in MD/VA dealers charge around 300 for the total service

OKAY, so I got the car back. The tranny shifts like a dream now! Worth every single penny to have this taken care of. The car's never shifted so perfectly through the gears. NOW, here are the mistakes that MB made that I noticed after formally testing the car out:

1. Paddles only work in M mode, not S or C. However, the shifter works for down/upshifts.
2. The C has now been replaced with a W... as in (W)TF or Winter

They either programmed the wrong model into the control unit or put in one that was made for an SL500/600. Greaaaat, now I have to get it back to the shop tomorrow =(

Total cost out the door was $1,799, in case anyone was interested. But if you're having the same funky tranny issues, definitely have this fixed as it will give you a whole different driving experience!

Cheers,
-Long

My newly purchased CPO certified 24K mile SL 55 with AMG performance package was jumping into neutral after the shift to second under hard acceleration, and the only way to get back in gear was to pull over and stop, shift to park, and then drive. Needless to say it was no fun, embarrasing, and worrying to me, and more so if someone was in the car with me.
Well, brought it in, and I now have a new torque converter. Drives as it should so far.
Lucky it's a CPO car!

The required maintance for the trans on a SL 55 is a 1st service Fluid and Filter change at 40,000 miles.

What part number is on the housing around torque converter, mine has a 210# on it. Is this what you guys have?

I forgot to conclude this thread.. so the update is that they installed a 2003 TCU (I have a 2004), hence the W mode. It was duly replaced and everything works as it should now. Until something else breaks, I'm a happy camper.

Cheers,
-Long

how did u solve the noise/ humming sound issue ... Did you replace the oil to a higher viscosity grade ??
I just got my car done (trans fluid change) and have the same noise like wind noise ..... and I hate it

I don't drive the car very much, so I haven't gotten another oil change yet. I'll reply to this post when I get around to it and will let you know the results.

Cheers,
-Long