Torque Converter Slippimg
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Torque Converter Slippimg
While driving I was using my iCarsoft scanner and came across the torque converter. It showed that it is slipping about 15-20 rpm when locked.
Should the locking hold it totally or is it made to have this small amount of slip?
Should the locking hold it totally or is it made to have this small amount of slip?
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Joined: Nov 2011
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From: Austin, TX
2013 SL550 BiTurbo
Full disclosure: I don't know what the acceptable lever of "slip" is, but seems pretty insignificant...could just be a data acquisition differential between the input and output sensors???
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From: V E G A S
1922 Ford Model T / no OBD
20 rpm might be instrument tolerance.
To confirm it, drive with steady speed and observe the rpm change when you let gas pedal go.
If the converter really slips, you will see jump in engine rpm.
To confirm it, drive with steady speed and observe the rpm change when you let gas pedal go.
If the converter really slips, you will see jump in engine rpm.
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From: New Orleans Area
2015 E400 Sedan
NOt sure on MB TC but most TC are a simple fluid coupling connecting engine to tranny.
So one part bolts to flywheel (outside of TC)
The other side is a shaft coming out of TC into Tranny to connect and transfer energy via the fluid inside.
So the outside has vanes and the shaft part has vanes that are spun from the outside vanes via fluid.
At low RPM there is a lot of slip (heat build up) to allow you to put foot on brake at stop lights and the engine not stall.
but as engine revs up the slip is constantly be reduce and more power is transfered to tc shaft in to tranny..
At some point we hit what is called TC STALL speed and this is the "Supposed" speed the engine and tranny will spin at the same speed.
Thing is since coupling is fluid there will always be inefficiencies so yeah RPM may be a bit different.
There is no mechanical lock up just fluid to transfer engine power to tranny..
See here a few good explanations:
https://www.mistertransmission.com/h...onverter-work/
https://auto.howstuffworks.com/auto-...converter1.htm
Now if MB in this car does it differently like has a Lock up clutch or uses a dual clutch or something - then ignore above and have a nice day.
So one part bolts to flywheel (outside of TC)
The other side is a shaft coming out of TC into Tranny to connect and transfer energy via the fluid inside.
So the outside has vanes and the shaft part has vanes that are spun from the outside vanes via fluid.
At low RPM there is a lot of slip (heat build up) to allow you to put foot on brake at stop lights and the engine not stall.
but as engine revs up the slip is constantly be reduce and more power is transfered to tc shaft in to tranny..
At some point we hit what is called TC STALL speed and this is the "Supposed" speed the engine and tranny will spin at the same speed.
Thing is since coupling is fluid there will always be inefficiencies so yeah RPM may be a bit different.
There is no mechanical lock up just fluid to transfer engine power to tranny..
See here a few good explanations:
https://www.mistertransmission.com/h...onverter-work/
https://auto.howstuffworks.com/auto-...converter1.htm
Now if MB in this car does it differently like has a Lock up clutch or uses a dual clutch or something - then ignore above and have a nice day.
Thread Starter
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
Likes: 1,293
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
NOt sure on MB TC but most TC are a simple fluid coupling connecting engine to tranny.
So one part bolts to flywheel (outside of TC)
The other side is a shaft coming out of TC into Tranny to connect and transfer energy via the fluid inside.
So the outside has vanes and the shaft part has vanes that are spun from the outside vanes via fluid.
At low RPM there is a lot of slip (heat build up) to allow you to put foot on brake at stop lights and the engine not stall.
but as engine revs up the slip is constantly be reduce and more power is transfered to tc shaft in to tranny..
At some point we hit what is called TC STALL speed and this is the "Supposed" speed the engine and tranny will spin at the same speed.
Thing is since coupling is fluid there will always be inefficiencies so yeah RPM may be a bit different.
There is no mechanical lock up just fluid to transfer engine power to tranny..
See here a few good explanations:
https://www.mistertransmission.com/h...onverter-work/
https://auto.howstuffworks.com/auto-...converter1.htm
Now if MB in this car does it differently like has a Lock up clutch or uses a dual clutch or something - then ignore above and have a nice day.
So one part bolts to flywheel (outside of TC)
The other side is a shaft coming out of TC into Tranny to connect and transfer energy via the fluid inside.
So the outside has vanes and the shaft part has vanes that are spun from the outside vanes via fluid.
At low RPM there is a lot of slip (heat build up) to allow you to put foot on brake at stop lights and the engine not stall.
but as engine revs up the slip is constantly be reduce and more power is transfered to tc shaft in to tranny..
At some point we hit what is called TC STALL speed and this is the "Supposed" speed the engine and tranny will spin at the same speed.
Thing is since coupling is fluid there will always be inefficiencies so yeah RPM may be a bit different.
There is no mechanical lock up just fluid to transfer engine power to tranny..
See here a few good explanations:
https://www.mistertransmission.com/h...onverter-work/
https://auto.howstuffworks.com/auto-...converter1.htm
Now if MB in this car does it differently like has a Lock up clutch or uses a dual clutch or something - then ignore above and have a nice day.
I believe there is a mechanical clutch (disk brake) inside the torque converter that locks the two halves together when their speeds are nearly the same but I'm not sure.
I also thought that this minimal slip (20 rpm vs 1800 rpm engine speed) could be an error in the speed reading(s). I do not feel any problems at all, just noticed it while scanning around with the iCarsoft. It shows with capital letters SLIPPING when it should be locked at steady highway speed on flat. Also shows the same going slight down hill.
I'm not sweating it, just wondered if it should be zero speed difference over the converter.
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From: V E G A S
1922 Ford Model T / no OBD
So -called converter lock is more like a brake, so when it engages, there should be zero difference.
Than without lock, the differences are in 200-300 rpm range, so long way from 20.
Than without lock, the differences are in 200-300 rpm range, so long way from 20.
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Joined: Aug 2019
Posts: 594
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From: USA to Germany
W221/W222/W213/X290
Drive on the highway at about 50 MPH, put the transmission in Manuel mode and hit the gas pedal all the way down (don't press it so it clicks. This will put the transmission in the lowest gear. Just press it all the way down without clicking). See if the RPM's spike up or misbehave. You should see a little bit of play in the RPM but very very small movement. I've had to replace my transmission as mine was slipping (from driving over 120,000 miles without every changing out the oil or the filters).
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Drive on the highway at about 50 MPH, put the transmission in Manuel mode and hit the gas pedal all the way down (don't press it so it clicks. This will put the transmission in the lowest gear. Just press it all the way down without clicking). See if the RPM's spike up or misbehave. You should see a little bit of play in the RPM but very very small movement. I've had to replace my transmission as mine was slipping (from driving over 120,000 miles without every changing out the oil or the filters).
My scanner shows the TC clutch OPEN when I come to stop. This is when it shows slip speed as the engine speed, naturally. Then I start driving it goes from OPEN to SLIPPING showing slip speed up to 50 rpm as I did some more observations on this. Still about "nothing" comparted to engine speed.
I believe it is a speed reading error. Anyway, my transmission is smooth and if that slip is actually true then I rather have it than not. Still going 25 MPG at 80 MPH so no problems here.
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Joined: Aug 2019
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From: USA to Germany
W221/W222/W213/X290
I did all moves I could think of. Hard acceleration, hard engine braking, steady speed driving at highway speeds as well as steady speed city driving.
My scanner shows the TC clutch OPEN when I come to stop. This is when it shows slip speed as the engine speed, naturally. Then I start driving it goes from OPEN to SLIPPING showing slip speed up to 50 rpm as I did some more observations on this. Still about "nothing" comparted to engine speed.
I believe it is a speed reading error. Anyway, my transmission is smooth and if that slip is actually true then I rather have it than not. Still going 25 MPG at 80 MPH so no problems here.
My scanner shows the TC clutch OPEN when I come to stop. This is when it shows slip speed as the engine speed, naturally. Then I start driving it goes from OPEN to SLIPPING showing slip speed up to 50 rpm as I did some more observations on this. Still about "nothing" comparted to engine speed.
I believe it is a speed reading error. Anyway, my transmission is smooth and if that slip is actually true then I rather have it than not. Still going 25 MPG at 80 MPH so no problems here.
Cheers
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
I messaged my buddy in Boston Mercedes and he said that it's most likely either an error with your computer (need the STAR one to properly diagnose) or it's going to be fluid pressure. He said that if the pressure is not up to par and spec it will make the trans slip and lag. He asked me when was the last time you've changed your tranny oil and filter, and at what interval you've done it at.
Cheers
Cheers
I have had my transmission fluid changed at every 40 000 miles as this is what the service booklet calls for and every time this was done at a MB dealer service. I have 167 000 miles on it now so last time was 7 000 miles ago and this last time I asked to see the oil pan just to see how much material the magnet collects and it was almost all clean. I drive highway 85 - 90% so I could probably get by changing the fluid at 60 000 miles or even 80 000 miles but as the transmission is so important with the engine to keep the car going I still do the transmission service every 40 000 miles like I change engine oil every 5000 miles. My engine does not burn a drop of oil between changes and oil is so clean after 5000 miles it is difficult to see on the dip stick.
But, back to my converter slipping. I do not feel any kind of problem when I'm driving so I think it is a bad speed reading either on the engine speed or the turbine speed. I may just get me a strobe light so I can check the exact engine speed to compare to what my iCarsoft shows...
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Joined: Aug 2019
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From: USA to Germany
W221/W222/W213/X290
Thanks Pablochacon for your troubles going to ask your buddy!
I have had my transmission fluid changed at every 40 000 miles as this is what the service booklet calls for and every time this was done at a MB dealer service. I have 167 000 miles on it now so last time was 7 000 miles ago and this last time I asked to see the oil pan just to see how much material the magnet collects and it was almost all clean. I drive highway 85 - 90% so I could probably get by changing the fluid at 60 000 miles or even 80 000 miles but as the transmission is so important with the engine to keep the car going I still do the transmission service every 40 000 miles like I change engine oil every 5000 miles. My engine does not burn a drop of oil between changes and oil is so clean after 5000 miles it is difficult to see on the dip stick.
But, back to my converter slipping. I do not feel any kind of problem when I'm driving so I think it is a bad speed reading either on the engine speed or the turbine speed. I may just get me a strobe light so I can check the exact engine speed to compare to what my iCarsoft shows...
I have had my transmission fluid changed at every 40 000 miles as this is what the service booklet calls for and every time this was done at a MB dealer service. I have 167 000 miles on it now so last time was 7 000 miles ago and this last time I asked to see the oil pan just to see how much material the magnet collects and it was almost all clean. I drive highway 85 - 90% so I could probably get by changing the fluid at 60 000 miles or even 80 000 miles but as the transmission is so important with the engine to keep the car going I still do the transmission service every 40 000 miles like I change engine oil every 5000 miles. My engine does not burn a drop of oil between changes and oil is so clean after 5000 miles it is difficult to see on the dip stick.
But, back to my converter slipping. I do not feel any kind of problem when I'm driving so I think it is a bad speed reading either on the engine speed or the turbine speed. I may just get me a strobe light so I can check the exact engine speed to compare to what my iCarsoft shows...
My brother had a W212 2012 and had transmission problems at 109,000 miles. It just goes to show that you with 167,000 miles and it's still functioning and he with 62,000 miles less had to get rid of his car completely because of the tranny. I've read people had issues at 35-50K on the 722.9 trannies.
Best of luck. Hope it's nothing major!
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MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Anytime! Sorry I cannot be more help. It sucks when you cannot see something online haha.
My brother had a W212 2012 and had transmission problems at 109,000 miles. It just goes to show that you with 167,000 miles and it's still functioning and he with 62,000 miles less had to get rid of his car completely because of the tranny. I've read people had issues at 35-50K on the 722.9 trannies.
Best of luck. Hope it's nothing major!
My brother had a W212 2012 and had transmission problems at 109,000 miles. It just goes to show that you with 167,000 miles and it's still functioning and he with 62,000 miles less had to get rid of his car completely because of the tranny. I've read people had issues at 35-50K on the 722.9 trannies.
Best of luck. Hope it's nothing major!
