GRP

My 2010 pre facelift has recently developed harshness with the transmission.

Started with there being a bit of "vibration" on cold idle - no longer the quiet car with a great exhaust sound. At first I thought exhaust system but I think the trans may be the cause. Transmission cold engagement from park to drive is now a solid thump and fwd movement. Not as pronounced once you have been driving and everything is up to temp.

Trans was serviced as per log book 18 to 24 months ago.

Done 65K klms/40K miles.

Eurocharged V5 tune.

Any thoughts?

mthis

Does this happens in Drive/reverse when u hold the brakes ?

GRP

Not as bad in reverse as in drive.

If I cycle via reverse briefly the thump into drive is less.

Hand brake is on.

mthis

sounds like that?

AMG893

Have you tried resetting the adaptations?

If you were in Sydney, i would offer for you to come over and i would plug in the Star Diag and properly reset the TCU

GRP

Thanks for the offer.

Will try a full reset.

roadtalontsi

i have no idea what that is a video of. sounds like an exhaust leak or something.

mthis

In my video.
Engine mounts and trans mounts and trans was low on oil.
did a trans service and replaced the mounts and no more noise.
I think all that is due to all the drag racing and having LTH that had to remove the shields for the mounts. 55k miles. did 3 trans service so far.

ritalin

What do you do for a trans service besides fluid?
Im thinking about doing one early.

GRP

Reset - did not fix my trans issue but otherwise reawakened performance. Should be an annual exercise.

Video - I could not make out what I was meant to be hearing but I think not.

Simply a delay when you shift to drive and drive engages with a firm thump sound/jerk.

GranSport

I have the same issue. Only when fluids are cold. When I put gearbox on D mode and holding brake, I can hear exacly the same noise and fell like something is knocking.

Just few hundreds miles ago I had full service, all fluids and filters are new.

So I believe the engine and gearbox mounting ("pillows") should be replaced...

mthis

Yea. going by what the shop did thats what fixed my issue. btw now the engine has no play before it moved alot.

GranSport

Hope it helps!

Did happen only with cold fluids or even after warming up?

Colin G

How do you reset a transmission? I have a 2008 C230 4matic. I feel the performance could be a little sportier.

MJames2

it isn't your transmission ...it's the diff ...my car does something similar ever since i had a wavetrac installed ...anyways MB's looked @ my transmission because i asked and theres nothing wrong with it, it's the diff ..maybe your OEM diff is going bad.

anyways don't worry about it, unless you haven't ever serviced your trans and have slip. I've driven 50,000km+ with the "diff thump" and 0 issues besides the thump when it's cold from P>R>D

Conv_GSDriver

I'm also hearing the same the OP is describing, same symptoms, when cold starting to shifting to D. Not every single cold start, but it does happen.

GRP

I had wondered if it was my Wavetrac but the issue did not immediately follow diff installation. Engine and trans mounts have had the all clear at last 2 services where I specifically requested they check carefully. I still have the issue but over time it has "settled" and is less invasive (or perhaps I have learned to tolerate it).

Jasonoff

Probably just backlash. Did you get the spec from the shop that installed your WaveTrac?

How much play is in your drive shaft?

GRP

I will check it myself when I throw on new rotors and pads in the near future. If it is the diff, I will be pissed as I paid good additional money for a diff specialist to set it up.

Jasonoff

If the backlash increased it wouldn't be the installers fault. There's no shims.

It could be anything like others have suggested. You have huge motor that's spinning at ~700RPM and a DT that is at 0RPM. You shift it to drive and the torque converter needs to absorb that difference of RPM to slip but not before the DT slack is taken up.

That jolt could be any of the mounts in the DT, the backlash being taken up in the diff etc. There's too many variables so we can only give you suggestions to inspect.

mr747

and if you used who i think you used you paid told dollar also

SmithyWings

hi James, I am having the same issue as you. However I got this thumb type noise with my original open diff at first, then I changed to a wavetrac and I’m still getting it. I’ve had my gearbox inspected and the only thing wrong was a clutch plate inside which is now repaired but it’s still happening. Can you describe exactly what’s happening to yours? Does it only happen when you reverse and then again into drive? Mine also does it when in manual mode downshifting.

Would love to hear how you got on with yours.