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My attempt at replacing the transmission plug.

167K views 158 replies 55 participants last post by  MBGraham 
#1 ·
This afternoon I went ahead and changed out my transmission harness plug/ connector, the how to's that are around for this are pretty good but I was still not sure going into it how to remove it so I decided to snap some pics of the process.

What the underside looked like, when I first jacked up the front end.


Pull down the wire connector (fastened with a clip) to reveal the screw that holds the shield in place.


There's a star pattern screw hidden away under that harness that I just pulled out of the way, unscrew it.


Once the bottom screw is removed, simply push the thin metal shield out of the way revealing the connector.


Better look at the connector.


Twist the plastic white tab towards the bottom as the arrow indicates. The twist motion pushes out the wire harness connector.


Once its released, pull it out the rest of the way, out of the way.


This is where the problem comes from... the oil leaking into the wires, as you can see its drenched in oil.


There is a 7mm bolt in the center of the connector where the arrow is pointed.


7mm setup to unscrew the bolt.


This will allow you to pull the connector assembly out, this is i the part you'll be replacing. Closer look at the connector you'll realize that you did not have to purchase the whole connector, rather just the two o-rings that go bad over time. The connector only cost $15 from the MB dealer, the o-rings would've been $1-$2, so not a huge savings there either. The o-rings I'm referring to are pointed out by the red arrows.


Once you pull out the connector, this is what you should end up with.


The old and the new connector.


The new connector in place, with the 7mm bolt tightened.


From then on, just work backwards. The whole process took less then 30 minutes. In my situation the transmission fluid is very dark and will be replaced here very soon.

Kruso
 
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#141 ·
#142 ·
Here are the documents, complete with the Photobucket pictures. One for the transmission connector and one the TCM cleaning (due to forum . I uploaded them to BenzWorld so they're here regardless of what 3rd party hosting services may do in the future. Thanks again to Kruso for these great documents.
 

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#143 ·
How much transmission fluid will spill out when I remove the plug if I have the car level on a lift? How much fluid would I have to suck out with my Mityvac through the dipstick hole to prevent any from spilling out? I think I have the transmission fluid level perfect right now so I'd like to keep it that way. Thanks.
 
#147 ·
I opened the apparatus case this morning. Found some oil on the plug from transmission. This is after changing the transmission connector a while back. Not enough to be worried about, but just noting that changing the plug may not cure the problem.
 
#148 ·
I have a mb 2004 c240 4matic. I was passing someone and a bunch of tranny fluid began gushing out. When i stomped on the gas it would squirt on the exhaust. My 13 pin adapter is leaking on the inside of the plug. Could it squirt alot of fluid out under load?
 
#151 ·
Have you seen or read how to change the connector bushing ?
Yes ,when you take the harness out ,spray the plug until clean ,,
Best is to use genuine MB 236.14 spec fluid ,,or Shell atf 134 or Fuchs ,,,any fluid that is 236.14 spec..
You also need a proper mb style dipstick to set the fluid level correctly.
 
#154 ·
I was passing someone and white smoke started rolling out behind me and everyone behind me turned on there windshield wipers i pulled over on the side of the highway and the whole underside of my car was covered in tranny fluid sprayed and dripping everywhere. It sat for a couple weeks and its on jackstands and i checked the 13pin connecter when i unplugged it tranny fluid started running out. Im hoping thats the only leak. Fixing it tomorrow.
 
#157 ·
Thank you for sharing. Its alwasy good to see fellow mb owners sharing there work and experiances. If I may add my 2c. The small 7mm nut that holds this in place, for crap sake, do not over tighten it. you WILL, SNAP it OFF!
 
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