c43 grinding noise in P and N

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zaen1

Active Member
Joined
Apr 10, 2015
Messages
91
Location
Birmingham
Car
c200 sport/c43 amg
Hi everyone,a problem has started with my c43 gearbox. I drove it a couple of miles today and when just a few mins away from home i heard a clonk kind of noise,i parked it up straight away and put in into P and a grinding noise was heard,i changes through all of other gears and the grinding noise is heard in N as well, i have not driven the car since,too scared i might cause more damage, on the way home driving i did floor it a bit at the lights,other than that just normal driving,can anyone help please,its sunday and i cant even take it to a garage or anywhere to have it looked at. Gutted:(
 
how many times did you change the oil since you bought your car?
do you floor your car when it's below work temperature?

if you're unlucky, tranny might need to be replaced because it will look like this inside with shrapnel?
 
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Flooring it away from the lights when it's making nasty expensive noises will not help.
Get it trailered to a specialist who knows his way round that gearbox,they are a bitch of a thing for breaking things and that includes bank balances and credit card limits. My indi who is one of the most experienced merc trained guys on the planet will not touch them.
 
how many times did you change the oil since you bought your car?
do you floor your car when it's below work temperature?

if you're unlucky, tranny might need to be replaced because it will look like this inside with shrapnel?

I have had the car for a few months only,oil was changed on car at around 90k,current mileage is 127k. The car was well warmed up before i decided to floor it which i dont usually do. If it is a rebuild how much would i roughly be looking at. Is their any checks i can do myself?
 
there isn't much you can do yourself.

there is no dipstick behind engine as it's sealed with a cap to check level.

best thing to let a garage do this for you so you don't fukk up anything?
lift the car and unscrew the tranny-bolt to see if there's any metal shavings mixed with oil?
i put a magnet long time go inside my tranny, if there is any shavings magnet will pick this up.
 
Just started t he car agian after a couple of hours,the noise is still their but not as loud as it was before,it still drives fine,smooth gear changes etc but that grinding noise in N and P is more of a humming noise now,just realised both front brake pads are almost worn out,could this cause the noise in N and P gears.
 
apply foot on brakepedal and put the stick in D, do you hear any funky noise from tranny?
you should hear brakes make some noise when you have foot on brakes.

worn pads should give you warning illumination on cluster
 
No funky noises from tranny when applying brake pedal in D only pedal goes down deep with that air sound when pressing the pedal
 
Stop driving it you will only make things worse. Worn brake pads would give you a grinding noise if they had gone metal to metal,but the low pad warning light would be on long before that happened,this is assuming that the car has the right pads fitted with wear indicators. Get it scanned up on star before you do anything else and that includes driving the thing,it will not improve with driving if it has bits of metal breaking loose in the box. It may well explode internally then you are in big money trouble.
 
Does it make the whirring noise in P & N with engine on while stationary in your drive with no foot on the brake and just the rear brake applied?
If 'yes' than its a transmission noise.
Get the pan off and check for metal debris.
 
Give a call to Olly (BlackC55) on here. He will have the solution for you.
 
£1200 sounds cheap for a full rebuild , no?
 
The 722.6 has a fine reputation for reliability on planet Earth.
Light years ahead, they were. And also used by Jaguar.

Weren't the C43 ones a bit different, hence their poor reputation? I believe some of those who have put a 5.4 engine in a C43 have also used the donor tranny too. Or do I detect a smidge of tongue in cheek there?
 
Does it make the whirring noise in P & N with engine on while stationary in your drive with no foot on the brake and just the rear brake applied?
If 'yes' than its a transmission noise.
Get the pan off and check for metal debris.


That is exactly what is happening,is it hard to get the pan off?
 
Dropping the pan is easy drain the fluid and measure how much comes out undo the six torx bolts and it's off.
 
There might be a drain plug on the torque convertor on your model depending on year.
Drain, measure fluid that comes out. If you drain the box & TC then iirc its 9 litres.. But best to measure as you'll get an exact amount.

As said a ramp/axel stands, goggles, torx driver, rubber gloves, new gearbox filter, merc gearbox oil and fingers crossed for no swarf.. In your situation you've got little to loose trying it yourself.. Infact I probably wouldn't bother buying the new filter and oil until the pan was off..
 
Having no ramp or axel stands and having a spinal injury i have booked in at MSL on tuesday morning,will update once they have had a look at it
 

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