faverodefavero

Here goes the full story...

First the facts and a small introduction:

I have a Coupe P30, it says P30 in the official car documents, at the description of the car model, really: 'C63 AMG P30 Coupe' is exactly is it goes.

My VIN is WDDGJ7HW9DG089082 and my car has 487hp.

My car leaves two tire marks when launching - with launch control or with everything on manual and traction control fully OFF (not sport handling mode) and manually launching - 90% of time, and leaves two tire marks as well, when sliding on corners a bit, around 70% of time (tough, SOME times I can see smoke coming out of just one wheel and just one mark, but it's really rare).

I do get some hard rear wheel sniping "hop" when in the wet and/or bad asphalt or uneven terrain.


With all that in mind, here comes the question, please stay with me:

I'm not sure my C63 has the AMG OEM rear locking differential (40%)...


It has the P30 code in the official AMG building sheet, and in the very manual of my car it says my C63, for having the P30 Performance Package, has the Locking Diff from AMG.
I contacted an AMG engine builder, a German lady that's a relative to a close friend of my, and she said that - even tough my car does not show the exact code, 471, for the AMG 40% locking differential - every AMG car that has the P30 code has a locking differential.

BUT, and here's why I'm not so sure my car has the locking differential: I tested lifting the whole car, 4 wheels on air, and spinning one wheel slowly while in Neutral (car turned off) and got no positive tradition from the not manually spun wheel, it just wobbled a bit to the opposite side (less the 2cm, really small opposite side wobble from the "un-manually-spun wheel" tough, I say that because I've seen rear tracking cars without any kind of locking or limiting differential really spin the opposite wheel a lot to the different direction than that of the forced wheel).

Speaking with my dealer I got the information that I want to check with you guys: that the C63 AMG P30, has an AMG locking differential and not a "real" limited slip differential and hence does not lock the wheels up to 40% while at neutral and don't engage at all unless enough tracking difference (slip) is induced in one of the rear wheels, at which point (and only then, also only when accelerating) the differential will finally lock and snap.

Is that all correct? If so, any way I can really, 100% sure, test my car to check if it does has a locking AMG OEM rear diff? Care to, please, explain how (since the lifted in neutral wheel spin search for positive tracking clearly does not apply to such a spring locking differential and only to real LSDs such as yours)? Thank you very much for this -- I can't really find solid information on automatic spring AMG OEM locking differentials and how to properly test them and their functionality properly anywhere.

Searching online for "automatic locking differential" (and NOT limited slip differentials), I DID got into many explanations that stated that such and automatic locking rear differential would not, indeed, engage in neutral and would only do so under very specific wheel-slip detection situations with the clutch engaged, all that is within the lines of how I'm told the 'AMG 40% automatic rear locking differential' works in the C63 P30.

Can anyone that owns a C63 with the original AMG factory OEM differential confirm this, please? That the locking mechanism will not engage while at neutral with all 4 wheels lifted and car turned off and will only engage in said conditions? I'd really like to see a video if possible, of a C63 P30 doing tests for the OEM locking diff..

I just really, really, want to be 110% sure of what I got. Trully.


Thank all very much for all the attention, really. And hope I can get some nice answers from you.

avery.whss

if youre leaving 2 tire marks after a launch you probably have the factory lsd in ...or you can just turn off ESP and do a burnout thats the easiest way to see if you have 1 tire fire or not..if it leaves 2 marks you have it..if it's 1 burnout mark then you don't

the stock AMG diff isn't even a LSD i dont think, pretty sure its a open diff or something because both tires spin @ the same time

faverodefavero

What should I check for the burnouts please? Also: can anyone with a 471 for sure post a video for me of the tests, please? Thanks for the help so far.

realjones88

I ran your VIN, it looks like you are in Brazil? I am not an expert on Brazil, but in the US C63 coupes only come with the LSD as an additional option and not included in the p31 performance package (which is listed as p30 on the build sheet).

You have 923 for the engine horsepower increase, U70 for the red calipers, etc so it appears your option package is similar to the US. My guess would be that in Brazil the LSD is not included in the performance package either.

However, you do not have code 471 on the build sheet therefore you do not have the LSD. The factory is not going to put something on the car that isn't on the build sheet.

Mazspeed

Wrong. I have a non LSD and often leave 2 tire marks. If the difference in breakaway is not that great on either side, it will act similar to an LSD while not being an LSD. In the turns it will always act as if its not.