C43 "False Neutral"

[Feeble]

I have a C43 AMG and my dad was driving it the other day. He briefly put his foot to the floor to drop a gear, and let off very quickly. The car appeared to slip out of gear and made a clunk, and only revved when he tried to accelerate. He pulled over to the hard shoulder, put it into park and then back in drive and it seems to be fine again...

Is this nothing to worry about, or is it a sign that somethings not right with the gearbox? My feeling is that the car didn't expect him to let off so quickly, as the same has never happened when I drive it...

Any advice greatfully received...

 

[whitenemesis]

Could be the beginnings of an electroplate failure, or could be ATF level is low.

Check the fluid level and get the codes read.

 

[Feeble]

That doesn't sound good... Better to catch it now than let it get worse though eh?

 

[Feeble]

What are the chances that it's nothing though? Zero..?

 

[sallison1504]

It wouldn't do something like that for no reason. Sounds like low AT fluid. I'd have it topped up, or changed.

 

[andy27168]

Hi Matt,
Take the car to Olly at PCS and get it plugged into STAR and the codes read first see if there is any related to the gearbox, as the 43 doesn't have a gearbox dipstick get him to check the oil level and top up if needed at the same time.

 

[IanMSpencer]

On my W202 C240 I had that symptom, turned out that the piping to the auto box cooling radiator sprung a leak.

Hard acceleration would make it drop out of gear - started with a clunk, ignored it to the point of near failure. Nearly knackered the gearbox, but fortunately a couple of oil changes and some specialised treatment rescued it.

Get it checked.

 

[Feeble]

Thanks guys, doesn't sound too bad! Glad I've caught it early! Will get the gearbox oil changed as soon as! Don't know when it was last done so it was kind of on my list of things to do... Thanks again!

 

[m2287]

If you have any oil on the floor you probably have a leak somewhere... I had this exact problem on my 55 afew months ago!

 

[andy27168]

If its gonna be a little while till you get the GB oil/filter changed I would still get the oil level checked.
When you get the GB oil changed get them to replace the pilot bush as well (approx. £20 from the dealer) as these are the most common cause of a leak on the 722.6 box, the oil wicks along the wiring loom to the TCU (inside the car) and if the leak has been there long enough the oil soaks into the sound proofing in the front floor well.

 

[Feeble]

Thanks for the advice chaps. It turns out that I know somebody who is a auto gearbox specialist (who'd have thought...) So I will take it to his garage on Friday for a fluid level check. Thanks again for everybody's input!

 

[Feeble]

I had the ATF level checked and it needed another litre adding... Hopefully that should cure the problem! The guy said the gearbox feels good and he couldn't see any signs of it needing anything more at the moment!

 

[BlackC55]

If it still does it I expect there to be lack of pressure in the box. It will need to be removed, stripped and inspected to find the issue.

 

[Feeble]

Fingers crossed it's all over now. Like I said, it has only happened the once, so I'll just have to play the waiting game now... Or perhaps not let dad drive it again! Or tell him to stay in 'old man mode' when he's driving lol

 

[nb_racing]

Definitely worth getting the oil and filter changed. They always get neglected and it's generally considered the common cause of gearbox problems. PCS (BlackC55) do a good deal on getting it done.

 

[Feeble]

What sort of price are we talking olly?

 

[andy27168]

I had the ATF level checked and it needed another litre adding... Hopefully that should cure the problem! The guy said the gearbox feels good and he couldn't see any signs of it needing anything more at the moment!

Where did the fluid leak from would be the question I would be asking, if you have no record of the fluid being changed, then I would really get it done, as these gearboxes do have a reputation of self destructing, and as the gearbox is specific to the 43 finding a second hand one is nigh on impossible.

 

[Feeble]

Cheers Andy, I did get a quote from the guy I know, and it is something that I will do in the not too distant future!

 

[E300dave]

give cole a ring @ mbs southampton great indie you wont go far wrong there tbh...

 

[BlackC55]

£180 with a flush.

I have a 43 so know them very very well.