gixxerboy

I dont know of anyone that makes after market rear differential gears.
So my clk 550, has 2.65 gears, a clk 350 has 2.82 and i looked a c300 has 3.07's.
Does anyone know if they are interchangeable ?

Fatz

Quaife makes torque sensing differentials.

gixxerboy

I'm aware of that, but i want to change the gear ratio also, So im trying to see what other merc shares the same rear differential size but different gear ratio. That way i can upgrade both.

gixxerboy

I see our differential is the same that is some chryslers. Could i buy parts that go for a charger/ challanger 300 and have it fit our rear?

Fatz

I'm sure you've done much research on this. Just keep in mind that a lot of engineering went into that drive train. I would look at what MB uses for the AMG versions of the platform. Of course, you may have a specific use/purpose that would drive you in a different direction.

gixxerboy

the clk63 uses the same gear ratio as the 550 A 2.65 gear ratio The black series uses a 2.82.
2.65 is not really performance oriented. These engine do have allot of torque so they still do accelerate quickly. I'm assuming part of that gear ratio is to make up gas mileage and it is a mercedes.
So pretty much at minimum i want to upgrade to the black series ratio but would like to go a little more if im going to spend the time and do the 3.07's out of a 300

So does anyone know if a c300 share the same size differential so that the ring and pinion would be interchangeable? Or can anyone point me to a place to ask?

floridawriter

My 05 CLK55 has a final gear ratio of 3.06. I would guess the gears themselves to be interchangeable.

gixxerboy

Thank you, Just called dealer, the c55, clk55, and c class wagon all ave the 3.06 and will fit my car. At my discount they are $1480, ugh

But know i know what fits im searching junkyards for those cars, hopefully i can pick up a used diff cheaper. and a quafi differential.

do they make anything to be able to adjust the speedo? It would be the same thing as changing tires sizes

gixxerboy

struck gold got a rear diff out of an 05 clk55 cab. 3.08 gear less than $400. Now to get a quife or wavetrack. Might as well put in an lsd first. Still cant understand how amg's came with open differentials

kb24forlife24

Can you confirm that the 3.06 gears would work with a CLK500 2005?

gixxerboy

the differential i got was an of an 05 clk55 with 3.06. so i would assume. The ring and pinions seem to all be interchangeable just different ratio's in different models. The dealer told me a c class wagon rear differential would also work

eteller

Wow I once pulled a diff out of a 318i for the 3.73 gears and it had a LSD!

2MCHCAR

I don't see any mention of updating the TCU in this gear ratio thread. My car has the 5 speed transmission and in order to change a gear ratio properly, the TCU has to be updated to take into account the new gear ratio (or else the car will go into limp mode almost immediately). There are only 3 tuning places I know that can do that TCU update, Weistec, Kleemann and Eurocharged.

Your car has the 7 speed and I am not familiar with that transmission (I defer that to rudney), however I also believe your TCU must be updated for the different gear ratio or else it will go limp too.

Lots of Mercedes "projects" have been killed by software compatibility issues, I advise you get the software part flushed out before you start ordering parts.

Good Luck!

Rudeney

Hmm, regarding the transmission/TCU issues, the speedometer should be OK as it uses the wheel speed sensors. However, the transmission also has internal speed sensors. I just don't know if they would get "confused" or not. Unfortunately, I suspect that could be a problem if the TCU sees the shaft spinning at rate incongruent with the expected vehicle speed.

gixxerboy

I manage a transmission shop. My builder didn't think it would be an issue. Monday i will call our corporate tech line and Kleenmann , they did my tune and see what both think about it

kb24forlife24

Nice, I'd like to see what they say. Keep us posted.

gixxerboy

Spoke with Kleemann, there apparently there is a computer in the rear differential, its also married to the car by vin# He is looking into reprogramming my original to a new gear ratio. Hopefully he can. It would cause in issue with the traction control. He said the older 5-speed cars wouldnt be an issue, its the 7g cars that would have a problem

kb24forlife24

So Kleemann can change your original differential to new gearing?

gixxerboy

waiting to here, i would physically do the change, but there is a control module in the read differential, that would need to be programmed to the new gear ratio. He is getting with his programmer to make sure he can do it. So i would just send them the module. So its still up in the air

kb24forlife24

I'll be awaiting the news lol

gixxerboy

ok, so i heard back from kleemann. I was wrong about the module in the diff. Its the module in the transmission. They can program it to the new gear ratio. its $1095, but they have to send it to their Denmark location. So it would take time. I'm going to try Renntech and some other programmers to see if anyone else can do it.

kb24forlife24

What's the module that you have to send? Do you just say what gear ratio you want and they'll do it for you on the factory differential?

gixxerboy

its the transmission control module i have to send them to program to the new rear differential ratio. I assume they can do any ratio. I'm going to do 3.06's. He said they do it all the time over there

kb24forlife24

Isn't that a lot of labor to remove that module?

gixxerboy

no, not even an hour, just drop the trans pan. changing the actual rear differential will take longer

Know that i know it can be done. Im checking with other tunners to see if they can do it without sending over seas