Johncl63

Car is 09 CL63 AMG 87,000 miles full MB history but no evidence of a gearbox oil change

Ok so back to an old issue that despite visiting several amercedes specialist AND Auto Box Specialist no one wants to commit to a fix.

So here goes.

Symtoms.

NO fault codes in gearbox.

Any speed or rev range a SLIGHT touch of the throttle results in a violent judder/shudder that feel like its coming from the middle (just forward of the centre are rest) OR rear left. Described as driving over a cattle geid or rumble strip. Does it in sport, comfort, but less so in manual. Lots worse on an incline and lots worse at lower revs.

The other morning we had a slight frost, i started the car and let the womdows defrost, the car was in comfort, put into drive and before i could get my foot of the break the car lurced forward and stalled. This happend twice. It also did it on reverse. Tried to go from neutral to drive and it stalled. Put it in sport a few mins later and it still lurced but managed to get my foot of the brake and get going. This morning not as cold and i got away first time. One its been run it doesnt do it again on start up.

On wide open throttle there is NO issue it pulls hard.

The car has NO missfire, as thats what a few people thought and to be fair it did have a missfire. I baught this car to keep, icknow they are money pits but hey, you cant take it with you! So to fix the missfire i replaced both intake gaskets, all inectors, all spark plugs and oil breather and all Coils (coils i could if got under warrenty but im inpatient!)

An abs sensor was down so that has also been replaced.

Drove train we have changed the centre prop bearing and had it balanced. Both of the other 2 prop fixing look relatively new.

Gearbox oil level is ok.

Now given what happend to me in the morning its deffinatly making me go gearbox. But no one wants to commit to what it is in the box. I still say torque converter.

Here is a vid. While its not very loud on the vid beleve me when i say in the car just imadgen youve gone over a rumble strip at 70 and feels like a cattle grid at 80! Also not when it does it the revs rise ever so slightly before going back down.

bmwpowere36m3

I'd suspect TC lock-up... should be able to test with Xentry to force max engagement. If problem improves, you know where to start looking.

chassis

I am not surprised a shop will not commit to a fix. A 12 year old high performance German vehicle? No way.

Sounds like torque converter and/or lockup clutch. Have you replaced engine and transmission mounts? Have you thoroughly inspected the underside of the transmission and the transmission ECU cable/connector? What did you see?

Johncl63

Everywhere has been unable to force max engagement, im in the UK and mercades have removed the feature from Star

Johncl63

Trans mount is good, engine mounts need changing. Ill change them but mercades wont give me the part numbers! I want to get the parts from Autodoc! But due to the stall issue on the cold morning it leads me to believe its definitely something in the gear box rather than just the mounts.

Whats the difference betwee the torque convertor and lock up clutch? If i replace the torque convertor does that also replace the lock up clutch?

I know the easyest answer is to just get the box pulled and looked into whitch is whats going to happen next week im just looking ofr advice as its driving me crazy. Ive always thought torqe convertor but it baffle me why it doesnt do it on full throttle, i can do a standing start and hit the gas hard and pull way past 100mph with no issue at all, i would of thought the torque convertor would if been under most stress in these circumstances rather than just as per the video (ive now made it viewable)

chassis

The lockup clutch takes the torque converter out of the torque path.

Lockup clutch = plate type clutch where the input and output shafts are locked together. It's used when driving at constant speed to improve fuel economy and reduce emissions.

Torque converter = hydrodynamic "clutch" where the input and output shafts rotate at different speeds. It's used to increase effective gear ratio and to smooth speed changes while shifting gears and to allow the engine to idle while the transmission is in drive/vehicle stationary/zero output shaft rpm.

Arrie

Touching the gas pedal causing the strange vibrations could be from the TC lock-up opening up and this would explain the increase in engine RPM but why in the world would the lock-up clutch open from touching the gas pedal.

Does your gear box change down when you touch the gas pedal too?

I don’t know how mb TC lock-up clutch works. Is it spring loaded with oil pressure opening it or the opposite way?

If it is spring loaded to close then it needs sufficient oil pressure to open. Your trouble with cold morning start in this case could be indication of oil pump issues. Cold oil would not pump enough to get the TC clutch open and this would mean you have solid shaft connection thru TC to gear box and car stalls right when you engage a gear. After enough tries the oil has warmed up and pumps to TC to open it up.

But this would only apply if the TC clutch is spring operated to close.

BOTUS

as I said on the other forum have a chat with alexander foti, he's quite clued up on gearbox adaptions, STAR and gearbox fun of the quick ones....

Johncl63

Little update.

We were going to pull the transmission out. Bit something in my head said just do a oil and filer change for the hell of it. The oil that came out of the main box was ok, but the oil that came out of the tauque convertor was a mess. It looks as though someone hadnt draind the TC. New filter and fluid and its now fine. Will see how long it lasts!

chassis

Can you please describe the fluid that came from the torque converter? "Mess" is unclear.

BOTUS

the trans fluid in the box is exactly the same as the TC, its pumped from the sump into the TC to pressurise (to avoid cavitation) and goes round and round, you may have found extras in the TC that didn't fall out because only half empties when you drop the sump

The TC on a Merc is made of the same material they make cam chains from.... its a bit like a choc bar that's been in a microwave for 30 seconds

Johncl63

i didnt do it i just asked the tech!

It has been checked for water and its ok.