SLK/R170: Question about the 722.6 transmission socket
Thread Starter
Newbie
Joined: Dec 2020
Posts: 1
Likes: 0
Slk320 2003
Question about the 722.6 transmission socket
I replaced the 722.6 electronic transmission socket. I removed the old revision of it with the white O-rings. I have a couple of questions:
a) Is the socket supposed to be liquid tight by itself? I installed the plug and I had ATF dripping but I'm not sure if I spilled it or it was leaking from the socket,
b) How much does the transmission tolerate an overfill? I might have put like 6 quarts but I'm not sure because I spilled some. I want to turn on the engine and then measure the liquid. The dipstick marks it as beyond full. What should it show with the engine not yet turned on after a full liquid swap?
Thank you for the help guys.
a) Is the socket supposed to be liquid tight by itself? I installed the plug and I had ATF dripping but I'm not sure if I spilled it or it was leaking from the socket,
b) How much does the transmission tolerate an overfill? I might have put like 6 quarts but I'm not sure because I spilled some. I want to turn on the engine and then measure the liquid. The dipstick marks it as beyond full. What should it show with the engine not yet turned on after a full liquid swap?
Thank you for the help guys.
Junior Member
Joined: Dec 2019
Posts: 64
Likes: 6
From: Northeast Pa
2001 SLK 2017 Chevy Bolt, 2019 Subaru Crosstrek
A little bit over like a 1/2 quart isn't bad, but if its way over it might push out seals, giving you big problems.
Why not drop the fluid in the transmission then refill it with fresh fluid.
When I bought my car it had 75K on it, the fluid definitely needed to be changed, I removed the pan replaced the filter then refilled and used the car for a week.
After the weeks driving I pulled the plug then refilled the trans, the transmission took 5 quarts with pulling the pan, 4 quarts removing the plug.
Clean transmission fluid will help your transmission last longer, I know that for a fact.
Why not drop the fluid in the transmission then refill it with fresh fluid.
When I bought my car it had 75K on it, the fluid definitely needed to be changed, I removed the pan replaced the filter then refilled and used the car for a week.
After the weeks driving I pulled the plug then refilled the trans, the transmission took 5 quarts with pulling the pan, 4 quarts removing the plug.
Clean transmission fluid will help your transmission last longer, I know that for a fact.
Newbie
Joined: Mar 2013
Posts: 4
Likes: 0
From: Ma
Glk350
Also wondering if the plug (connector) is "sealed" from trans fluid, my connector was soaked and I dont see how the plug base can be sealed. The pins at the base and three holes in the base are not sealed and appear open to the conductor plate which I believe is drenched in atf during operation. What am I missing?
also lost a over a quart of atf after pulling the connector out, and the front of the car was jacked way up.
also lost a over a quart of atf after pulling the connector out, and the front of the car was jacked way up.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
Starting it to check the fluid level is fine. Don't drive it or leave it running for extended periods until you verify the fluid level, if it's overfilled and aerates the fluid it can burn things up in the trans fairly quickly under load.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
The plug is supposed to stop fluid, but it's a poor design and they leak through the pins as you noted, often filling the TCM with trans oil. This is why that part is replaced every time you are working on the trans, to help stop the leaking.
Junior Member
Joined: Dec 2019
Posts: 64
Likes: 6
From: Northeast Pa
2001 SLK 2017 Chevy Bolt, 2019 Subaru Crosstrek
Also wondering if the plug (connector) is "sealed" from trans fluid, my connector was soaked and I dont see how the plug base can be sealed. The pins at the base and three holes in the base are not sealed and appear open to the conductor plate which I believe is drenched in atf during operation. What am I missing?
also lost a over a quart of atf after pulling the connector out, and the front of the car was jacked way up.
also lost a over a quart of atf after pulling the connector out, and the front of the car was jacked way up.
The price difference between the plugs was too little to bother buying the original MB part.
Here is the part. https://www.autohausaz.com/pn/2035400253
Newbie
Joined: Mar 2013
Posts: 4
Likes: 0
From: Ma
Glk350
After studying this more I see the back side of the base with the 13 pins is never supposed to be exposed to ATF, it is the inside of the conductor plate which is supposed to stay dry. I made a false assumption thinking the beck of the pins (the conductor plate side) were exposed to ATF.
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Junior Member
Joined: Dec 2019
Posts: 64
Likes: 6
From: Northeast Pa
2001 SLK 2017 Chevy Bolt, 2019 Subaru Crosstrek
With mine I bought the new plug then while I was changing the trans fluid I installed it.
I took it apart cleaned up all the wires with brake cleaner dried everything off with shop rags then I put it back together.
My car did not leak from the plug but it was wet inside when I took it apart.
The reason I took it apart was because I heard about the problems with this plug destroying the harness, so for 10 or 12 bucks I wanted the worry gone.
I love my little Benz I just took it out of the winter storage garage, where it has been in hibernation since late last fall.
I took it apart cleaned up all the wires with brake cleaner dried everything off with shop rags then I put it back together.
My car did not leak from the plug but it was wet inside when I took it apart.
The reason I took it apart was because I heard about the problems with this plug destroying the harness, so for 10 or 12 bucks I wanted the worry gone.
I love my little Benz I just took it out of the winter storage garage, where it has been in hibernation since late last fall.
Last edited by beeguz; Mar 30, 2021 at 03:24 PM.
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