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Hello guys. My CLA250 is just out of warranty and the rear diff is acting up. I was looking to swap in a rear diff off of a crashed CLA and see if it would fix it since Mercedes wants $5000 for the repair. My question is has anyone tried this yet? Is it plug and play or does Mercedes need to re-learn this replacement diff? Is it going to fully just reject this donor differential since its not "new" or "unmarried"? Any help is appreciated.

P.S. I tried calling my local dealers for information and no one is picking up the phones..
 

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Just a reman diff is already 2500 ... sure hope you can source a good condition used unit ... seen some on ebay from wreck yards
Do you see any wiring harnesses? If not then you should be ok
Whats the existing one doing now?
 

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Still trying to source a compatible one on eBay. Apparently there were a few diffs made, as I encountered multiple part numbers already. The only connector attached to the diff is a solenoid plug.. which probably tells it when to engage 4MATIC.. so unfortunately it looks like I may be over my head. I managed to call one dealership and they said the car will have to be brought in to "relearn" the diff. Going to get a second opinion from another dealer.

This is the service bulletin i've been following. https://static.nhtsa.gov/odi/tsbs/2015/SB-10057753-2481.pdf

-Noise from the rear axle
-Unplugged the solenoid and the noise went away
 

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Oh ... bad solenoid ... partial engagement maybe?
Check which p/n is just a supersede those have bugs ironed out
 

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Oh ... bad solenoid ... partial engagement maybe?
Check which p/n is just a supersede those have bugs ironed out
I only notice the clunking noise when low speed turning in a parking lot or at a stop. Straight line has minimal noise.

From what I can tell, the whole carrier assembly (rear diff) needs to be replaced as its all one piece.
 

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From what I can tell, the whole carrier assembly (rear diff) needs to be replaced as its all one piece.
Well the bad one has to go before something else gets damaged
If you disconnect the diff control plug and drive is it quiet?
The relearning part is interesting ... wonder why
 

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I just got mine checked out by the dealership. Same deal. From dead stop to 30km/h, clunking noise at random frequency, gets to almost a popping sound if take off with a left or right turn. Definitely the rear diff. MB service disconnected the solenoid, which disengaged the rear diff, and noise disappeared. They ordered a new one from Germany and will replace under warranty. Having said that, I also wonder about the "re-learning" the rear diff. That part seems odd. Take it to other garages and ask them.
 

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Mine has the same issue and I just dropped it off. Anyone know where to get used reconditioned part?? They gonna call me tomorrow and I'm scared to find out repair cost.
 

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eBay?
Need to get correct p/n or supersede for your model year
Online benz parts sites may help as they refer to vin
 

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Mine is getting replaced at the dealer. I’ll post the part number once I get the repair invoice.
Hopefully from there one can track prior and subsequent year part numbers to trace the supersede history
And which are obsolete (and avoided)
 

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I was wondering if anyone installed the pedal commander or something similar before all this happened? I had the PC on my car for 2 days, which amplified the noise. Now I’m wondering if the PC may have accelerated the differential failure?
 

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pc is pedal sensor position remapping and associated ecu/tcu responses (well at least to first order) and if the diff cant take a little power curve remap it was dead anyway just a matter of time before giving up and klunking
 

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pc is pedal sensor position remapping and associated ecu/tcu responses (well at least to first order) and if the diff cant take a little power curve remap it was dead anyway just a matter of time before giving up and klunking
True. PC increases throttle response to the front wheels, and the rear diff is failing. And it seems like the failure is with the solenoid that engages 4Matic; 4Matic seems to be locked in place as if the car is losing traction when it’s not. If PC is somehow causing a cascade of mechanical failure and premature diff failure, it could be something to stay away if you have a 4Matic. This is all an unproven theory based on pure speculation. That’s why I’m asking others if they had PC installed before their diff crapped out.
 

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True. PC increases throttle response to the front wheels, and the rear diff is failing. And it seems like the failure is with the solenoid that engages 4Matic; 4Matic seems to be locked in place as if the car is losing traction when it’s not. If PC is somehow causing a cascade of mechanical failure and premature diff failure, it could be something to stay away if you have a 4Matic. This is all an unproven theory based on pure speculation. That’s why I’m asking others if they had PC installed before their diff crapped out.
Awww man can you imagine the PR nightmare for Vitalen if their gadget gets linked to premature Benz diff failures?
Though you have a point ... might be some secondary effect that screws up the solenoid? Recall the old days of turning a tube tv on and off until it killed the electron guns?!
 

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Car is fixed. Attached is the screen shot for part numbers and comment.

At least I won’t have to deal with diff oil change.

 

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Car is fixed. Attached is the screen shot for part numbers and comment.

At least I won’t have to deal with diff oil change.

very odd ... can't see the original picture of your repair order on the phone nor on the pc but replying to your post brings it up? must be a bug ...
remind me ... they had to order the diff or just happened to have it?
and there it is ... the "programming of 4matic" etc
well at least you got that oil change out of it ... just like my gearbox :cool:
 

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They ordered it. Took nearly a week for everything. On the bright side, I got a pretty well equipped 2019 C300 with Sports Pkg as loaner. That thing was smooth and torquey compared to previous years. I almost wanted to make an offer on a new C300 when I came back...
 

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this may be kinda odd ... just tested out the new C300 ... still don't like it? i dunno ... maybe my cla has brainwashed me or something ... and still don't like the vertical flip switches much prefer the tactile press buttons less to bump into in normal driving (or in an accident where any protrusions suck)
yes it is a bit roomier? though it still does not flog around corners as well ... and its still kinda boring :cool:
maybe the >2021s will be more appealing
 
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