I have a 2003 C230 with 1.8 liter engine. The stock 3.27 rear end is just too low geared, many times in drive I am at 1500 rpm.

I ordered a 3.67 rear end from Richard Jaques at Potomac German Parts. It cost $550 plus shipping.

There is another 2003 Coupe, with stick and 2.3 liter engine that put a 3.67 rear end in. He had no ESP problems.

I am slightly concerned about the automatic transmission "computer". I know about the Abbott Electronic Ratio Adapter so my speedometer will be OK. I am hoping it will also take care of the transmission and ESP issues. Does anyone have additional information to help me with this swap? Thanks


Richard Jaques at Potomac German Parts has two more C240 rear ends, 3.67!!!
I confirmed they are from C240's.
He has no 3.47s in stock, a whole pile of 3.27s and 3.06s.

The 3.27s would be a good compromise rear for the C32's

He has a couple more in stock, price is right
Call 1-800-831-7686

The speedometer won't be affected. The speedometer receives speed information from the ABS/ESP computer, which in turn receives speed info from the wheel speed sensors. I believe it only processes the left front wheel speed signal for the speedometer function, not 100% sure on that. But at any rate, a change in gearing shouldn't affect anything that I am aware of, there is no speed sensor in the differential that I am aware of.

Gilly

I think you will be in for a surprise!

I have swapped diffs and it will screw with every thing.

The tranmission controller looks and N2 and N3 speed sensors and compares them to wheel speed. If it is more than 3% difference, it will go into limp.

I have a way of re-coding.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Donnie:
But my statement about the speedometer not being affected is accurate?

Gilly

Benzmac

The web site for your shop is awesome, but you are a long way from Los Angeles.

Please let us all know about your re-coding. What is involved and what do we have to do to have you recode it. Cost is always important.

"The tranmission controller looks and N2 and N3 speed sensors and compares them to wheel speed. If it is more than 3% difference, it will go into limp."

Where are these N2 and N3 speed sensors, can the Abbott Electronic Ratio Adapter be used to input into these sensors?

No, they are also compared to the rpm sensor and the torque converter.

The difference is in the 4 sensors on the wheels as compared to the N2 and three.

If you change a few bits and bites in the trans controller, the car will think that diff came in there and all will work as it should.

If the control unit is shipped to me, I can do the work.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Donnie,
You seem to be the only person arround who knows what he is talking about. The rear end was just shipped this week, so maybe by the first week in September it will get here.

Which control unit are you talking about, the engine ECU that is mounted on the M271 Engine side? If there is another transmission computer let me the part number and where it is located. It may be easier to just buy another computer if it is not the engine ECU.

PM me on the price and how long you need the computer

My brand new Mercedes Benz C Class rear end arrived barely a week after ordering it (8 days exactly) from Potomac German Auto. Part number A 203 351 00 08 makes it for a W 203 C Class, supposedly for the anemic C 240?

attached photo of entire assembly. Only was $40 shipping cross country.

Attached Thumbnails

 

And here is the photo of the Magic 3.67

I assume we all have the ratio stamped in the same spot, should be easy to read from the rear, on a lift

Attached Thumbnails

 

Stick it in and see what happens. If it doesn't work correctly, email me.

Benzmac@peachparts.com

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Donnie,
Where is the control unit you are talking about. The engine ECU is extremely easy to take off in the 2003 Coupe. Is there another controller?

The "bits and bites" (bytes?) he's referring to must be a change in the version coding in the transmission control unit. Don't know what would be changed to make the transmission control unit respond to a change in axle ratio, possibly by changing the entire chassis type to say a C230 Kompressor, or whatever type that would have that rear axle ratio.
I believe the transmission control unit is also located in the control module box, near the engine control unit, you should see a label that will have, along with lots of numbers and bar codes, the letters "ETC".
Good God, the whole car is like a box of control units on wheels!

Gilly

The 2003 ECU is mounted on the drivers side of the engine, part number A 271 153 44 79

Here is a photo:

Attached Thumbnails

 

Can you post a wider angle image of that area?
That almost looks like the esp/abs control unit on the side of the abs pump, not sure. The ETC control unit should be in the module box. The image you posted also shows the service port for the AC, which also leads me to believe this isn't the correct module.

Gilly

On the two that I have done, I have found them in the passenger's foot well area behind the plastic or metal cover.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS