cl65intx

Hi All,

So last night I took the cover off my ECU/TCU box on my '05 CL65 to check fuses, connectors etc and I noticed that there was quite a bit of oil in the bottom of the box that the ECU / TCU sit in.

It's light weight so I'm thinking it might be from the ABC system - does anyone know what oil carrying components run close / next to the electronics box that would have sprayed / collected in there?

I'm hoping it's not oil leaking someplace and traveling along the wires back to the box!!

I't due into the dealer Monday to swap out my IC pump (preventative vs dead) but wanted to see if you gentlemen had any thoughts?

Cheers everyone.

2003 S600

Transmission fluid. You need to replace transmission connector on transmission. Old o-rings leak fluid and it climbs up wiring harness to TCU. Clean it out b4 you need a TCU also.

cl65intx

Many many thanks - I'll get it replaced.

FormulaZR

This is old, but I believe it's the ABC. Jo @ Speedriven was talking about this with me just a few days ago. It's at a connector, I believe?

Oxygen

It is actually a faulty seal on the electrical connector on the transmission. The cable harness runs directly from the transmission to the TCU and the transmission fluid actually climbs up the wiring harness and starts filling up the TCU with oil!

Luckily the oil is not electrically conductive.

cl65intx

Thank you all for the posts - yes it was the seal and it was tranny fluid vs. ABC - all replaced by dealer under ext. warranty :-)

hcetzneb

Just a side note.. On the v12 engines you also have the possiability of it being engine oil in the me-sfi ( engine ecu) It is common for the oil presure sensor on the engine and it wicks up the engine harrness.. Ive seen it mistaken for tranny fluid which is more common

ncoupe

I had the same story on my wife's 320 CLK. The leaky transmssion connector was replaced by a revised part under warranty. Problem was that the new part was also defective, the transmission kept losing oil and it almost fried. I installed a new connector (apparently MB's second attempt to get the part right), and it has been good since. By now MB probably has built the part for your car correctly, but check it for your own peace of mind. Another example of legendary early 21st century MB quality!

NRL

I have the TCU transmission leak in the tcu box, not that bad actually, just a bit, compared to other folks I've heard with the same leak. On the CL it insulates the tcu without any issues, but I'd like to stop the small leak.

I've tracked down 2 CL W215 part# for the connector near the transmission: O-Rings.
0269974148
0269974048
Is that all I need to swap out or do I need a new connector that connects near the transmission?
Also do I need to change out the harness connector that is at the end where the tcu box is?

biker349

wher does the abc leak come from? i've never heard of this.

NRL

I dont think it's ABC. It's transmission oil leaking past the oil ring on the connector, pushing some ATF oil all the way up the wire harness and comes out in the tcu box in the engine bay.. Mine had a small amount but for some people it fills up. It doesn't rally effect the electronic bathed in oil but I think it over fills and leaks out if you don't keep an eye on it.

I think the best route is to get a new inner connector with the 2 red o-rings, replacing it with a new designed one with 2 black o-rings.

FormulaZR

I was incorrect on ABC - I *meant* transmission fluid...

kk100

i know this is an old thread but some help would be appreciated.

I just took the tcu out of my CL65 and noticed that some oil is leaking from it similar to other posts here. I got the gearbox oil changed about 2000 miles ago - would this have anything to do with this??
Thanks

shardul

iTrader: (1)

there is a electrical connector on the transmission that goes bad. you will need to replace that. It costs about 30 dollars.

kk100

Thanks looks like I will be needing that - does anyone know the part number?

Also will the oil I in the TCU box do any damage to the TCU?

NRL

The new part has the better O-rings..
With the old original part, Oil leaks past it and wicks up the wire harness wire(s) insulation..

Lots of models and even Chrysler models have had that issue occuring before they came up with the replacement part with better O-rings.

I think it's ok with alittle oil, but might be an issue if it over fills it.

I have yet to pull the TCU out myself..

How do I lift the fuse box to get to it?

I'm sure it'll be easy after the first time.

shardul

iTrader: (1)

The TCU just slides out.
I have a space TCU from a 65 for sale.

kk100

You don't have to lift the fuse box out as the TCU is just behind it and not underneath. Simply slides out. At least this is the way in my CL65

NRL

Yah, is your hood at the extended up veritical position or just up normal?
I recall it was a bit tight to get a hold of it and get it out..
I think the manual mentions lifting the fuse box alittle to get at it easiler.

Thx

kk100

I just had the hood open normal. To be honest it takes a bit of fiddling about to get the fuse box cover off and after that it is simple to remove the TCU which is located on the left hand side of the fusebox. Slide the TCU up a bit and remove the multiplugs and that's it.

shardul

iTrader: (1)

small trick
after cleaning the TCU and putting it back flip it around and slide it in so the wire harness connector is on the bottom and not on the top of the TCU this will prevent fluid from going back into the TCU if it wicks up the wires again.

kk100

Thanks shardul I will do that. Do you know how to remove the housing of the TCU ? I was going to try and clean any oil from inside it but seems to be difficult to get off

NRL

o, nice tip

shardul

iTrader: (1)

you have to pry it open from the connector side. it is press it. Be careful because sometime when you try to pry it open the screw driver will slip and damage the PCB inside.

kk100

Thanks again!