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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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#32 · (Edited)
This is probably how it works:

The tranny fluid contacts the adapter in the middle section (between the two O-rings). The lower (smaller) O-ring prevents it from leaking into the connector. The top (larger) O-ring prevents it from leaking to the outside.

This explains the necessity of having two O-rings. It prevents leaking to two directions.
 
#38 ·
and now back on topic

or you could go with
"The difference between something that can go wrong and something that can't possibly go wrong is that when something that can't possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." from "Mostly Harmless"

same feeling as Zen but more direct :D

or the ever favorite
"If you try and take a cat apart to see how it works, the first thing you have on your hands is a non-working cat." by Richard Dawkins in his eulogy to Adams, always puts me in mind of the feeling when I pull one of the ECU's to check something - will it ever start again:(

and seeing as how we are so off topic I just have to add this from the triumph web site - I love it

HAMMER:
Originally employed as a weapon of war, the hammer nowadays is used as a kind of divining rod to locate expensive parts not far from the object we are trying to hit.

MECHANIC'S KNIFE:
Used to open and slice through the contents of cardboard cartons delivered to your front door; works particularly well on boxes containing seats and motorcycle jackets.

ELECTRIC HAND DRILL:
Normally used for spinning steel Pop rivets in their holes until you die of old age, but it also works great for drilling mounting holes in fenders just above the brake line that goes to the rear wheel.

PLIERS:
Used to round off bolt heads.

HACKSAW:
One of a family of cutting tools built on the Ouija board principle. It transforms human energy into a crooked, unpredictable motion, and the more you attempt to influence it's course, the more dismal your future becomes.

VISE-GRIPS:
Used to round off bolt heads. If nothing else is available, they can also be used to transfer intense welding heat to the palm of your hand.

OXYACETYLENE TORCH:
Used almost entirely for setting various flammable objects in your garage on fire. Also handy for igniting the grease inside a brake drum you're trying to get the bearing race out of.

WHITWORTH SOCKETS:
Once used for working on older British cars and motorcycles, they are now used mainly for impersonating that 9/16 or 1/2 inch socket you've been searching for for the last 15 minutes.

DRILL PRESS:
A tall upright machine useful for suddenly snatching flat metal bar stock out of your hands so that it smacks you in the chest and flings your beer across the room, splattering it against that freshly painted part you were drying.

WIRE WHEEL:
Cleans rust off old bolts and then throws them somewhere under the workbench with the speed of light. Also removes fingerprint whorls and hard-earned guitar calluses in about the time it takes you to say "Ouch...."

HYDRAULIC FLOOR JACK:
Used for lowering a motorcycle to the ground after you have installed your new front disk brake setup, trapping the jack handle firmly under the front fender.

EIGHT-FOOT LONG DOUGLAS FIR 2X4:
Used for levering a motorcycle upward off a hydraulic jack.

TWEEZERS:
A tool for removing wood splinters.

PHONE:
Tool for calling your neighbor to see if he has another hydraulic floor jack.

GASKET SCRAPER:
Theoretically useful as a sandwich tool for spreading mayonnaise; used mainly for getting dog-doo off your boot.

BOLT AND STUD EXTRACTOR:
A tool that snaps off in bolt holes and is ten times harder than any known drill bit.

TIMING LIGHT:
A stroboscopic instrument for illuminating grease buildup.

TWO-TON HYDRAULIC ENGINE HOIST:
A handy tool for testing the tensile strength of ground straps and brake lines you may have forgotten to disconnect.

1/2" x 16"-INCH SCREWDRIVER:
A large motor mount prying tool that inexplicably has an accurately machined screwdriver tip on the end without the handle.

BATTERY ELECTROLYTE TESTER:
A handy tool for transferring sulfuric acid from a car battery to the inside of your toolbox after determining that your battery is dead as a doornail, just as you thought.

AVIATION METAL SNIPS:
See hacksaw.

TROUBLE LIGHT:
The mechanic's own tanning booth. Sometimes called a drop light, it is a good source of vitamin D, "the sunshine vitamin", which is not otherwise found under motorcycles at night. Health benefits aside, its main purpose is to consume 40-watt light bulbs at about the same rate that 105-mm Howitzer shells might be used during, say, the first few hours of the Battles of the Bulge. More often dark than light, it's name is some-what misleading.

PHILLIPS SCREWDRIVER:
Normally used to stab the lids of old-style paper-and-tin oil cans and splash oil on your shirt; can also be used, as name implies, to round off Phillips screw heads.

AIR COMPRESSOR:
A machine that takes energy produced in a coal-burning power plant 200 miles away and transforms it into compressed air that travels by hose to a pneumatic impact wrench that grips rusty bolts last tightened 60 years ago by someone and rounds them off.

PRY BAR:
A tool used to crumple the metal surrounding that clip or bracket you needed to remove in order to replace a 50 cent part.

HOSE CUTTER:
A tool used to cut hoses 1/2 inch too short.

cheers
Barri
 
#39 ·
Very funny - and quite accurate. :D
 
#40 ·
Perfect description of garage mechanics. :thumbsup:

I'll also fess up that I have employed these tools as described in 2/3 of the examples, and suffered the consequences.
 
#46 ·
fdte320,

My $0.02. Get the OEM part.
I bought and installed the URO part only to have it leak 6 months later.

I had initial difficulty getting it to seat properly and used the center screw to pull it into position. Likely NOT a good decision upon hindsight.

When I replaced it with one purchased from the dealer it was a much smoother install. Still working a year later.

YMMV

Skippy
 
#49 ·
I'm with The King.

Even if mine was leaking, I wouldn't replace it with the URO part. It's not a bad job, but it is messy, you have to reset the fluid level each time, and you are guaranteed that the URO part will leak.

It's sort of like asking if you should replace your windshield with one that is all cracked or just get a nice one. ;)


BTW, I think it was FAB that found the OE plug on amazon for a great price, or you can get it at a Chrysler dealer for a fair price, much kinder than the MB dealer in that regard.
 
#51 ·
Yep. The current PN is 2035400253, I don't know if the number on that box is the corresponding dodge number, though. Maybe Eastb could clarify if the part in the box was in the MB bag with the MB part number?

At any rate, it is a standard stocking item at Dodge/Chrysler dealers.
 
#53 · (Edited)
replay

Just so no one tries fixing a leaking transmission electrical plug with an inferior product........

After reading posts of the URO transmission electrical plug not being up to par, I got a MB plug from the Chrysler dealership to compare with the URO plug previously ordered from AutohausAZ. (A MB part in a MOPAR box, not something one would expect to see, ask for adapter plug from a NAG-1 tranny from a 2002 Crossfire or part number 1-68021352AA)

A quick visual did not show any differences. A dimensional comparison of the plug bodies with calipers showed they were the same.

However, a dimensional check of the smaller O ring showed that the URO was thinner than the MB plug when installed on the plug. The upper O ring was also thinner. It is obvious on the photo shown below. Both plug adapters are new.

Once the O-rings were rolled off the plug bodies, the size differences became clear.

The smaller of the two O ring's is critical to keep ATF out of the conductor plate shroud connection (sealing location "1" - on photo)and the larger O ring keeps ATF from leaking to the outside of the transmission (sealing location "2" - on photo). A less tight fit of the URO plug may increase the chances of ATF leaking into the connector and wicking up inside the wiring insulation to the Transmission Control Module.

This past 6 months, I used a new MB connector plug on our ML and and suprisingly reused the URO body on the S class. For both, it was difficult to get the MB center 7mm bolt to engage than compared to the last time I changed a plug on our E420 – with a URO. Suspect that the smaller O-rings on the URO make for easier seating, but inferior sealing. Additionally, a closer inspection of the the center bolts between the two adapter plugs showed that the URO has an extra length of thread than the MB brand. This means that the center bolt will catch easier on the conductor plate cup (photo below, red circle.) If you cannot get the MB brand adapter in place, you may want to swap the MB O-Rings onto a URO plug body to take advantage of the extra thread on the bolt. This is what I had to do on the S, even after trying the tricks of of lubricating the O-rings with ATF and stuffing some paper towel inside the 7mm socket to get better seating force.

One more tip when you change the adapter plug - ensure that both of the O-rings come out with the old adapter. It will be nearly impossible to seat a new adapter with an old O-ring remaining in place.

Good Luck
 

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#54 ·
Very useful instructions and pictures indeed--thank you very much to Kruso! My car also shows some traces of oil on the bottom of the transmission casing, just as shown on the first pictures. I strongly suspect now that this plug is the culprit.

I have one question, though: on this picture, with the old plug completely removed, it seems that fluid is leaking out of the hole. How much fluid was this? And is it just a limited amount that had collected inside, or is it a small, but steady stream that won't stop until the new plug is installed (or until the transmission is empty :eek:)?

Thanks again!
 

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#55 ·
Hi, Simon.

If you have quality jackstands, just lift the front waaay up and secure everything to your satisfaction. That will ensure you get very little fluid out. It will also give you enough room to work under there without being too cramped.

Otherwise you'll get a flow of fluid, but it doesn't go on forever, maybe several ounces, though that's a lot to be dribbling around. And the plug is far enough above the pan that you couldn't run it empty, or even seriously low. Still, getting the front up pretty high will cut down the fluid loss to just a few drops

Good luck.
 
#59 ·
an easter egg

I noticed some fluid on my garage floor the other day. I thought was engine oil, but it is trans fluid. When I looked under the car, it looks like the fluid is coming from this same plug that you just replaced. Great pics! I'll pick up the part tomorrow and see about replacing it.
Thanks for the timely post.
 
#60 ·
I noticed some fluid on my garage floor the other day. I thought was engine oil, but it is trans fluid. When I looked under the car, it looks like the fluid is coming from this same plug that you just replaced. Great pics! I'll pick up the part tomorrow and see about replacing it.
Thanks for the timely post.
HELLLLPPPPP!!! what am i missing here? the part came out easy. getting the new part in is impossible. there must be something i am doing wrong. besides it being a sunday and i have no help. i can get the new part in the hole, but i can't get the 7mm screw to catch. it's been over an hour. help please. i'm talking about the transmission plug in the first part of the post.
 
#62 · (Edited)
thanks. i think i may have done it. it needed the extra push. now to roll it off the stands and check for leaks. Amazingly enough, there are no leaks yet after a 4 mile drive.
THANKS KAJTEK1. I appreciate the last bit of advice on the strong push to put the plug in place. I had visions of towing the car to the dealer tomorrow. It sure looked easier in the initial pics.
next week, the fuel filter.
and thanks to KRUSO for providing the steps in the first place.
 
#64 ·
Both o-rings came out. I just didn't realize that I had to push hard on the new part so that it would seat far enough to allow the bolt to catch threads and tighten. Maybe if I would have had it on a lift instead of at arms length while I lay on my back looking at it upside down I would have noticed.
Once I gave the new part a push, it seated and the bolt was too easy to tighten. It also didn't help that my fingers had trans fluid on them and they kept slipping. It was a tad annoying, but I'm glad it's on.
Question: Will this new part make any difference other than no more leaking?

Thanks for the 0-ring thought. It could have been that, but it wasn't.
 
#65 ·
Nope, its main function is to prevent leaking. Did you clean out the female plug/cable with MAF cleaner to get rid of any fluid before replacing it?
 
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