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Registered 1999 SLK230
Joined
114 Posts
Discussion Starter #1

I hear that noise in Park, it goes away when in drive or reverse. Transmission will intermittently not go into any gear at all, but will if I turn it off and restart the car. But if it does go into gear, I hear the sound in Park before it does. Seems like if I don't hear it, it won't go into gear. Stumbles in reverse or drive if I feather the gas, like its about to stall. But if I drive it normally it's fine. The sound faintly appears while driving at higher rpms on highway or when i come to a full stop, but only sometimes. Otherwise it's mostly quiet in gear and drives normally.

The sound seems to be coming from the passenger side, near the transmission. What would cause the sound to go away completely while in gear? I did check fluid and it did seem low, did not even appear on the cold mark. So I put a little in to go to the store and get fluid, also have the plug connector famous for leaks, filter, and plate and gasket ready to install too. Also, if I leave it in park with the sound still there, and I press the S/W button, the sound does change too....

I'm sincerely hoping that it's not a dead tranny or torque converter. It was shifting fine, except for 5 minutes before the sound started happening, where slowing down in drive to a stop sign, it jerked very suddenly once. Then 5 minutes later, the sound appeared.

Is there any hopeful chance that the low fluid and possible need of a filter/plug/plate would solve this? Or could this be an entirely different issue from the tranny, like supercharger?
 

Registered 2002 SLK320
Joined
1,758 Posts
Hi,

Very difficult to tell from Video, I take it you are referring to the "rapping tapping knocking" type noise ...............

If I were you I'd get it in the air and listen around the Bell Housing area ..................

Check that Torque Converter bolts are tight, may also be a cracked Flex Plate ("Flywheel"), it needs finding and fixing sooner rather than later ;)

HTH,
 

Registered 1999 SLK230
Joined
114 Posts
Discussion Starter #3
Yeah, that rap a tap tapping sound. When I put it in gear, it goes away completely. I'm putting it up today to take a look. Do the torque converter bolts typically come loose over time? As for the flex plate, that wouldn't have been damaged because of the spacer plug leak, right? Like, from the wicking of the fluid anywhere near it to corrode it?
 

Registered 2002 SLK320
Joined
1,758 Posts
Hi,

They can come loose, especially if someone has had them out before doing a Trans Repair etc and not torqued them properly ;)

Also Drive Flex plates are thin steel compared to a manual Flywheel and the do crack over time, putting the vehicle in gear / driving takes up the "slack" caused by loose bolts / cracks ;)

Oil leaks will not cause it ;)

Of course it could be something breaking up inside the Tranny, but lets hope not for now ;)

HTH,
 

Registered 1999 SLK230
Joined
114 Posts
Discussion Starter #5
Yeah, definitely crossing my fingers it's not tranny parts in there that I am hearing. I'm guessing the flex plates could potentially cause that sound? So far it seems like so many things that are unrelated components can cause such similar sounds....mounts, pulleys, low fluid, torque converter, rattling shields, etc.

Would a tranny filter get so clogged to the point that it would cause the transmission to make such sounds? I can't even imagine what a dry tranny might sound like as it is still in one piece...(can you smell the fearful hope? lol)

Thanks for the input Dave...I appreciate the ear. Anything to help with the anxiety helps me see the overall picture clearer.
 

Registered 2002 SLK320
Joined
1,758 Posts
Hi,

Blocked Filter will cause a whine, (Pump Cavitation) not a knocking / tapping ;)

Pulleys are more of a light rattly bearing type noise, mount's are a vibration ;)

Low Fluid, all sorts of other issues, not rattling / knocking ;)

I've never heard a T/C cause a knocking / tapping unless it's blown itself to bits and slipping or not driving, and that usually only happens on Diesels due to the torque they produce, but it is a possibility ;)

HTH,
 

Registered 1999 SLK230
Joined
114 Posts
Discussion Starter #7
Well that's some hope I can keep in my back pocket...thanks Dave! Once I get it in gear and get it moving, it doesn't seem to have any issues with shifting like normal. That sound - part lesson was very helpful!
 

Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
4,606 Posts
Did you do a visual check for excessive engine movement due to bad mounts? Put the car in park, open the hood, and post a short video of the engine running while you punch the accelerator and immediately release it.
 
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