Hey boys and girls, long time member, but I don't post much. Used to have a lovely W124 sedan (that I also manual swapped) about 10 years ago. Forums and myself were a lot more active then.

So, as the title says, I've successfully swapped my 2006 C55 AMG to a 6 speed manual. It was one of the easiest swaps I've ever done. There are probably more detailed threads, but I didn't do the work myself and my mechanic isn't the "take a photo as you go" type of dude. Neither am I, to be honest. So bear with me, but I know all the main points and what was done. So if there's anything not 100% clear, please ask. I'll reply in detail if possible.


Mercedes W204 C350 6 speed manual transmission

Mercedes W204 C350 pedal box



Mercedes W204 C350 manual front driveshaft section

W204 C350 flywheel, pressure plate and clutch. Flywheel is the 4+4 pattern.



W204 C350 4+4 flywheel bolted right in. Crank position sensor and starter motor fit right in.


Transmission installed in car



Along with the above main parts, obviously tranny mount, hydro lines, clutch cylinder and all assorted manual stuff was included. There's a little bracket that holds the shift linkage to the underbody that was missing, so we fabbed one up using Teflon and an off the shelf water pipe bracket.

So, after having the clutch re-dressed, whole assembly was cleaned and balanced. Removed exhaust, transmission, and driveshaft. When we test fit the transmission it fit perfectly, but the shifter was a couple of cm too far back, so I had to trim the lower console area to get it to fit properly. I think this is due to my use of a W204 transmission and not a W203 unit. The reason for this was that the earlier transmissions have a slightly lower torque rating, and a cable actuated shifter. The W204 unit is rod actuated. After trimming the console piece and getting creative with the foam isolation around that area, all was well.
We then installed a new flex disc, and attached W204 front driveshaft section to my OEM rear driveshaft section. Then we installed it in the car. It fit perfectly and is a 100% bolt on affair. The W204 transmission mount was a different thickness, and so it touched (barely) the driveshaft. We then used a W203 manual tranny mount and all was well.
After this, we installed the pedals and assorted manual transmission lines and hardware. The pedals are a bolt on part as well, but there's a problem if you want it to feel 100% OEM. Due to I'm sure a different footwell and cabin, or mounting point, the clutch pedal is noticeably higher than the brake pedal, and the brake pedal itself is a bit low. Pedal travel has changed, even though the brakes feel 100% normal and capable. It was also difficult connecting the pedals to the lines and clutch cylinder as a result. It all ended up working fine, but I don't like how it feels and am on the lookout for W203 pedals to fix it.

You can't really tell here, but the clutch pedal is like 10cm ahead of the brake. It bothers me and I can't comfortably access the dead pedal or the e-brake.




This is basically the end of the mechanical aspect of the swap.

Called a friend over who's a Merc tech and has STAR. He plugged in, told the car it was a manual, and tried to fire it up. And failed. The car also wouldn't let us remove the key. We couldn't really find a solution in STAR to solve that, even though the car accepted some part of the manual coding. The HUD changed to a manual configuration, but plugging in the scanner yielded a world of error codes relating to the auto tranny, and even a directive that basically said the car is an automatic but some monkey has coded it to be a manual. Fix immediately.
Sooooooooooooooooo my mechanic tried another way, which was removing the computer module from the automatic shift mechanism that was installed previously. He plugged it in, I believe kept it in P, and the car fired right up! We noticed that the soft start feature is gone (have to hold the key and twist, like a pleb).
After much beer and celebration, and making sure the clutch was bled and all was good in the world, I got in the car and gave it the beans while parked. Uh oh... soft limiter at 4000rpm. With a sigh of defeat, thoughts of a standalone ECU and weeks of headscratching filling my brain, I decided to take it for a spin around the block to see what it felt like. Gently at first, keeping it under 2000rpm, feeling for any odd vibrations or noises. It all feels perfect, smooth, balanced. While it doesn't look OEM right now, I promise you it feels it. No jerkiness, no issues.
Anyway, on my way back, I floored it in 2nd gear and lo and behold! It went to redline. Apparently the soft limiter is only when stationary, and apparently (according to a buddy) a manual C320 is the same thing. I felt quite silly, let me tell you. So, we hid that automatic shifter module inside the console, closed it all up, and I drove home.

This was last Friday and so far the car has been a gem. I've put about 200 kilometers on it now and I'm gonna start being a bit less conservative on the throttle since I'm confident nothing's gonna go wrong. I dyno'd it right before I swapped it with the intention of seeing how much WHP I will gain as a result of this. The file itself is ****, AFR is 11:1 and it made less power than I expected. But as a baseline to see my gains from auto to manual, I'm quite interested.

I've noticed a few little changes with the car, like the ESP's behavior. I didn't think anything would change, but I noticed the faux LSD effect is completely gone. It's 1 wheel peeling a LOT more now. If I have also inadvertently made it less intrusive that would make me a happy, happy man. I was thinking it's because it's still in P (the module I discussed above is set to P). I donno.

 

Forgot to mention.. car has Eurocharged mid length headers (made for a W211) and a EC tune. I'm not happy with the tune, the AFR is way off. Will be getting a custom dyno tune after I fab up the intake.

 

What was the WHP gain from converting to manual only? 10 WHP?

 

I'm curious about the what you guys did with the auto shifter module. Did you leave the electrics plate from the valve body plugged in ? Are there any error messages or lights on the dash? Great work btw!

 

Great work!

I’m curious as to why the use of the w204 parts? Just scarcity as I know the w203 was sold with about 3% manual in USA.

Here is a link to a great CLK320 conversion.
https://mbworld.org/forums/clk-class...sion-swap.html

I am also very curious on electronics, but, in the reverse. I have fitted Distronic to my w203, but it faults at ignition. I have an error between the ME and DTR unit. However, it is highly hypothesized that it faults due to a lack of a NAG transmission. Yet, no faults indicate that.

https://mbworld.org/forums/performan...ult-c1510.html

Love the swap, I’ve done it many times in many cars and waited 3 months for my w203...

 

Excellent!

I have pondered such an endeavor many times with my c55.

so to be clear, no adaptor plate is required between the new transmission to engine?

Thank you for sharing this, pretty invaluable info.

 

I think it should improve by ~5%. Mine made 326whp with a bad tune, so all things equal it should now make 342whp on the same file. We'll see, I'll share before/after dyno sheets when I get it done.

No adapter plate whatsoever needed. Tranny, shifter, driveshaft and pedals are all 100% bolt on if you use W203 parts, and I'd say 95% bolt on using W204 parts like I did. Trimming the lower console (the opening in the cabin where the shift mechanism comes out from) and not being satisfied with the pedal positions being the only difference.

This is probably the best thread I could have imagined. It's exactly the same process on the C55. Exactly. Well done for the writeup. I suggest anyone looking to do this swap use this thread as a guide. There are minute differences but it's mostly the same.
The reason I used W204 parts was because I couldn't find W203 parts. Mercedes cars in Lebanon are predominantly auto, and the kit I found was off of an imported C350 manual that was swapped to automatic to sell. I can't even find a W203 pedal box right now. Price was good so I went with it, paid $200 for the whole swap kit w/tranny.

Conductor plate is gone, and the plug that attached to it was tucked away. There's an SRS warning on the dash, but that's because I disabled the rear right airbag as my dog always chills on that side. Haven't gotten around to it. Otherwise no, dash is 100% normal. If you plug in a scanner though it freaks out and gives plenty of automatic transmission warnings. Need to code it again just haven't had the time.

 

Which particular transmission model is it that you used, and how does it feel in this application? I’ve never driven a manual mb before, have heard mixed reviews about the shift quality of their manuals etc.

 

Ok, so your comment that it made less power than you expected refers to the existing tune, with AT, not to the existing tune with MT.

 

Yes, exactly. I'm going to have it dyno'd on this file, and then custom dyno tune it right after.

 

Let me start by saying thank you for sharing this. Love the swap.
I would absolutely lose my **** if I could have this done on my C32

$200?! That sounds like a steal! How many miles did the W204 tranny have on it before you swapped?
​

 

I bought a eurocharged tune as well. Definitely not happy with it. It runs better on the stock tune. My car wouldn’t even start with the first tune they sent me. The second tune they sent me feels slower than stock.

 

BUMP THIS THREAD!!!

We need more people attempting and completing these swaps, it can create a new lease on life for this platform to the enthusiast world!!!

Hope to hear more soon on the progress. I am committed to doing this swap as well and documenting on my YouTube channel. Trying to gain all info necessary before beginning and buying parts.

Also, question to clarify, all you did to get the transmission to work ecm/tcu wise was keep the automatic gear selector plugged in and set to park, correct?

 

Very cool! Never imagined I would ever see someone do this.

 

Yes, but I also used STAR to reprogram the car into a manual W203.

 

Do you know the part number for the flywheel you used? or do happen to have pictures of the side you don't show above? Thank you!

Edit: part number for flywheel used here is 272 030 05 05 or Luk 415 0289 10

 

Hi and sorry for my bad english, I'm writing from Germany.

Just found that thread and read it with big interest because I am in the conversation of my 2000 SLK230K to 32AMG with Manual Gearbox.

- My donor-Car (RHD SLK32AMG) was delivered by transport company from UK to my house in Germany last week.
- I did not want that "old-style" Shifter linkage with rod and cable so i bought a w204 shifter linkage like yours and the gearbox from an SLK 171 350. I think that is the same like yours, too.
- Driveshat is from a R170 SLK 320

How is the 350-clutch asembly holding the torque of your engine? Is it strong enough?

My engine has different flywheel-pattern than in your pics, i could use the R170 SLK320 flywheel and clutch but i don't think that clutch will hold the torque... And i think, the 2-mass-flywheel will "go on block" under full torque.
So, I am thinking about using the rennsportfactory kit with lightended single mass and sprung fast road clutch (https://rennsportfactory.co.uk/produ...nd-clutch-kit/). But thats a bit expensive :-(

Cheers
Chris

 

Hey Chris, the OEM clutch and PP are dealing very well with the power level of my motor. There's also a 55K swapped W202 here that's running the same transmission and flywheel, but they resurfaced the clutch with copper I believe to handle more torque. Transmission will be fine as long as you don't drive it like a goon (applies to any transmission, really). I personally love the OEM feel of the dual mass and stock clutch. Lightweight flywheel will add some vibration and reduce drivability. My car will idle up a steep ramp in 1st with no throttle input. :P Lightweight flywheels don't like that kinda stuff.

 

Thank you very much for your fast answer...

Could you find coding in Star for your engine like in the 320-conversion thread?

Or do you still run the automatic gear selector set in Neutral? Is your cruise control working?

 

I did, and I told the car it was a manual in the appropriate places, but it still wouldn't start without the automatic gear selector for some reason. I think it's due to the version of STAR/the scanner we used. I intended to fix it but I've decided to leave the country next year, and don't really want to spend money chasing things that will not affect my enjoyment and use of the car. The gear selector module is tucked into the transmission tunnel, under the shift console. Not bothering me at all. Cruise control isn't working, but Lebanon is a very small country and I've actually never even used it. :P

I'm still going to re-tune it and put it on the dyno because I want it to be running at its best, but as of now, no more LSD, coilovers, air intake system, hybrid supercharger swap.. all my plans for this car are done. Just going to keep it tidy and clean for the next owner to enjoy it.. Wish I could take it with me, but it isn't allowed into the country I'm going to.

 

Thanks again for your answer.

sad to hear that you can’t take such a „unicorn“ with you.

 

So, my conversion is ready to run.

but in my case it is not working like it should.

i can start with gear selector in N and drive around.

but my ecu will not activate the supercharger-clutch so no boost at all :-(

will try to go the way with coding as soon as I can get my hands to a DAS system.

 

What needed to be modded on the 211 mid length headers ?

 

Someone here did the same swap on a 55K, and IIRC they deleted the clutch for the SC, so it's always on. I don't have very many details about that car, sadly.

 

The primary at the very bottom on the left side needed to be bent slightly so it wouldn't touch the body. The merge section basically, not the pipes themselves. If your engine mounts are tired, now's the time to upgrade them as tired mounts will cause it to rub like hell. Ask me how I know.