Oil leakage in W215 722.9 transmission socket
Thread Starter
Newbie
Joined: Jan 2026
Posts: 14
Likes: 5
From: İstanbul
W220 s500 w215 cl55 w639 viano w218 cls350
Oil leakage in W215 722.9 transmission socket
Hello friends, I'm new to the forum, I've had a w215 for a long time, I installed a compressor kit on my cl500 car and it became very enjoyable. I have a problem with the transmission, there is a constant oil leakage in the transmission socket connection part, especially in high speeds, there is hesitation in gear changes. I removed the conductive plate and changed the orientation of the socket. The oring coming out of the socket was strangely shattered, one side seemed to be burned, I think I suspect the exhaust temperature. I changed the 2 orings in the new rubber socket, the problem disappeared for a while, but now it started to do the same problem again. I would like to know your information and opinions on the subject, my vehicle is 2005 cl500 (m113 compressor kit installed) 722.9 with 7-speed transmission (also let me mention that 722.6 sensum was perfect, the new generations are terrible 😁
Member
Joined: May 2020
Posts: 247
Likes: 58
From: Fort Worth
2005 CL55 AMG || 2005 CL65 AMG || 1989 560SEC
Since it has been leaking, there is now transmission fluid in your Conductor Plate, which will destroy the electronics in the plate and make it the transmission work incorrectly until the plate is replaced. It is wise to replace the connector collar every 5 years or so.
You will also want to unplug your TCU and make sure it is not full of oil from the transmission. It will be very obvious if this is the case.
You will also want to unplug your TCU and make sure it is not full of oil from the transmission. It will be very obvious if this is the case.
Thread Starter
Newbie
Joined: Jan 2026
Posts: 14
Likes: 5
From: İstanbul
W220 s500 w215 cl55 w639 viano w218 cls350
Since it has been leaking, there is now transmission fluid in your Conductor Plate, which will destroy the electronics in the plate and make it the transmission work incorrectly until the plate is replaced. It is wise to replace the connector collar every 5 years or so.
You will also want to unplug your TCU and make sure it is not full of oil from the transmission. It will be very obvious if this is the case.
You will also want to unplug your TCU and make sure it is not full of oil from the transmission. It will be very obvious if this is the case.
Member
Joined: May 2020
Posts: 247
Likes: 58
From: Fort Worth
2005 CL55 AMG || 2005 CL65 AMG || 1989 560SEC
There should be absolutely zero oil visible inside the plug when you remove the wired connector... that is 1 of 2 jobs of the socket with the o-rings- 1: keeping oil inside the transmission and 2: keeping oil out of the conductor plate. Oil in the conductor plate is like water in your cellphone: nothing good will happen.
So... You can probably drive it like this for a while, but at some point it'll probably go into failure mode, which means second gear, only, all the time.
Looks like this guy had a similar problem-
https://www.benzworld.org/threads/72...g-atf.3166103/
***note on this post and the previous post-
I was assuming the 722.9 and 722.6 have the same intermediate removable collar that keeps oil in the transmission/out of the conductor plate. The 722.9 does not have this. it is built into the connector. Regardless, a failure of the O-rings will cause the same failure in the 722.6 and 722.9 transmissions.
So... You can probably drive it like this for a while, but at some point it'll probably go into failure mode, which means second gear, only, all the time.
Looks like this guy had a similar problem-
https://www.benzworld.org/threads/72...g-atf.3166103/
***note on this post and the previous post-
I was assuming the 722.9 and 722.6 have the same intermediate removable collar that keeps oil in the transmission/out of the conductor plate. The 722.9 does not have this. it is built into the connector. Regardless, a failure of the O-rings will cause the same failure in the 722.6 and 722.9 transmissions.
Thread Starter
Newbie
Joined: Jan 2026
Posts: 14
Likes: 5
From: İstanbul
W220 s500 w215 cl55 w639 viano w218 cls350
There should be absolutely zero oil visible inside the plug when you remove the wired connector... that is 1 of 2 jobs of the socket with the o-rings- 1: keeping oil inside the transmission and 2: keeping oil out of the conductor plate. Oil in the conductor plate is like water in your cellphone: nothing good will happen.
So... You can probably drive it like this for a while, but at some point it'll probably go into failure mode, which means second gear, only, all the time.
Looks like this guy had a similar problem-
https://www.benzworld.org/threads/72...g-atf.3166103/
***note on this post and the previous post-
I was assuming the 722.9 and 722.6 have the same intermediate removable collar that keeps oil in the transmission/out of the conductor plate. The 722.9 does not have this. it is built into the connector. Regardless, a failure of the O-rings will cause the same failure in the 722.6 and 722.9 transmissions.
So... You can probably drive it like this for a while, but at some point it'll probably go into failure mode, which means second gear, only, all the time.
Looks like this guy had a similar problem-
https://www.benzworld.org/threads/72...g-atf.3166103/
***note on this post and the previous post-
I was assuming the 722.9 and 722.6 have the same intermediate removable collar that keeps oil in the transmission/out of the conductor plate. The 722.9 does not have this. it is built into the connector. Regardless, a failure of the O-rings will cause the same failure in the 722.6 and 722.9 transmissions.
When I get a chance, I will remove the conductor plate again. I will share the progress here.
I have read similar topics to the posts in the link. I looked at most of the topics related to 722.9, but they did not explain the solution. I have mastered 722.6 sanzumans, I have been repairing my own vehicles for about 10 years. Mb world has been very useful to me in this regard.
Last edited by 5metre5litre; Mar 13, 2026 at 11:07 AM.
