Hello so I’m a college student who recently purchased a 2004 CLK500, the car was making a very feint whining noise on my way to college the first time I’ve ever noticed it. I thought it was just something stuck on a filter or of the sort. However it grew loud to the point it sounded supercharged so I was a little concerned. I parked the car and the next day I had an emergency come up in which I had to drive it. A few minutes of driving and I give it a little gas at a light (nothing crazy) and the transmission slips, all it wants to do is rev so now I’m looking like a touch at, it continues to rev and I’m having to rev a lot to get it to shift. I pull over at a gas station 20 sum minutes from my starting point, and it’s all neutrals, reverse just revs, drive just revs, manumatic just revs, I finally get it going very slowly hardly any power to the wheels but the motor is running perfectly fine. The car finally gives out and I roll into a private road. I try turning the car off and on multiple times and sometimes I can hear a clunk at the very first moment I start the car. Sometimes it doesn’t do it. This was late at night and I had to Uber back to campus. I’m hoping to get a scanner on it tomorrow as the engine light did come on when it first started to give out.. if it’s not towed. Anyone have any idea or experience something similar?

my thoughts
conductor plate
torque converter

I’ve heard these transmissions were really good and I wasn’t racing or anything exhorting a lot of stress just a mere heavy takeoff, surely this wouldn’t kill the torque converter..?

I’ve researched and people say the conductor plate is a common fault, however that piece seems to be purely electrical so in theory it wouldn’t product any whine or clunking when driving or starting the car.

now that I think about it, maybe it’s possible I snapped an axle?

my situation is really unfortunate, dad just got incarcerated, mom needs rides to hospital, I’m 3 hours away in college having to commute, not asking for sympathy just any help! Thank you

 

Mileage? Last time the trans fluid was changed? (Due every 40k miles)

 

Slow down and think through this calmly. The transmissions are not robust enough to surmount being driven when they should have been serviced. When you continue to drive while a car is making those sounds, you ARE damaging something. No free lunch here. If you ever find yourself thinking "I'll just limp it home" - - this is outright code for "I don't care if the engine dies".


Troubleshooting 101 - do not make wild guesses about which part is broken. Start with a methodical process of elimination. Axels on cars do not "snap" unless you have 500hp going through axles that came on a 200hp car and you are doing drag race launches at every stop light.

I can appreciate you are a college student that sounds like they don't know much about cars? If true, this may not be the time to learn in a stress free, economical manner. However, with Mercedes ownership comes the joy of purchasing many specialized tools - NONE more important than the code reader. While Autozone has OBD readers that you can use for free in their parking lot, the engineers at Mercedes designed a Mercedes-specific diagnostics code schematic that can only be read with a Mercedes-Specific reader. I use an iCarsoft MercedesII and it costs about $140 from Amazon.

STEP1 - Pull codes from the OBD2 computer port with the proper code reader. You can try using a generic OBD2 reader to pull codes (write all of them down) as it will at least give you something to diagnose from (Engine V Transmission).

STEP2 - Based o you saying there was a loud clunking noise, it does sound likely the issue is with your transmission. They aren't invincible, but since you didn't provide any information on the miles your vehicle has, how long you've owned it or any maintenance history, I'll assume all maintenance was deferred and you just purchased the car a few weeks ago. IOddly, Mercedes chose not to include a dip stick with these cars to check the fluid level of the transmission, but you can buy one from Amazon for about $10. Generally you check fluid level of a transmission while the vehicle is running, but this might not be possible in your case, so there is a "cold" level indicator.

 

EXACT same thing happened to me, same car. I checked ATF cold with curtain spring cord. Barely a reading, with nothing to loose, I poured a pint of ATF 4 red into tube. Started car and SURPRISE, it ran perfectly, smooth shifts too. BUT, still stuck with that whine that changes with rpm.

 

Start simple. Trans fluid and filter. Find a local shop as well.