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I'm in the fourth month on ownership of a new to me W212 E400. The car has 42.000km now and I got it with 41.000km. Right after I bought it, I had the local MB dealer inspect it and had all the overdue services done, which included the transmission oil replacement. I've looked the car when I bought it and the engine had oil seepage from the front camshaft adjuster covers (took care of those myself) but apart from that it was dry.
A few days ago I've noticed some oil on the back lower plastic cover. Called the dealer and they are booked all the way for two weeks from now, so I decided to put the car in a ramp to take a look while waiting. It was dirty with blue oil, so coming from the transmission. It is mostly on the right hand side of the trans close to the rubber grommet that allows access to the TC plug so my first tough was that is was leaking from it, but the TC is completely dry. Rotated the engine to inspect the TC plug and it was dry as well. Before cleaning everything, I've noticed:
There were traces of oil coming from the top of the transmission. Looking with a mirror, it seams to be from the breather valve
Most of the oil was dripping from the electrical oil pump mounted on the bell-housing. I don't think it was leaking from the pump however since there were oil on higher areas of the trans. I'm not sure if the electrical pump could leak inside the bell housing as well (I think it can't).
TC was dry and the part of the interior of the bell housing that I could touch with my finger was dry as well
Trans oil pan was mostly dry
There seems to be oil coming from the small drain hole in the junction between the bell housing and the trans main body
Now, I guessing the oil is coming (unfortunately) from the trans oil pump o-ring (A0169971448) since the TC and bell housing are clean (if oil was coming from a rotating unit I suppose it would have spilled everywhere). And replacing the pump o-ring means a lot of disassembly, way beyond what I can do at home.
Now, I know that replacing the trans oil doesn't causas new issues and if oil is now leaking it is likely due to the new oil being cleaner, but what got me wondering is the apparent oil that came from the breather valve. Is it possible that an overfilled transmission would leak? I have no means to put the car up and leveled to measure the transmission oil at home hence I just speculating at this point. I found on the forum some owners that had somewhat similar leaks but with much higher millage. Not sure if anyone had previous experience with this issue on low millage.
Thanks.
Last edited by Andre Cateb; 09-19-2023 at 09:06 PM.
Item 1 seems like tranny oil over filled
If overfilled too much, it may vent out I guess.
Item 5 seems like tranny oil seal
But car mileage is too low and age not old enough
Have you check the tranny oil cooler pipes ?
ADD: This one
Yes, the oil cooler pipes and connections are dry. I was hopping it was one of them as well. I had the same toughs on point #5... it's way too soon for them to fail.
P.S. Is this picture from your car? Do you know if the electrical pump has any way to leak oil inside the bell housing?
Sorry, I do not know much if the aux electric tranny oil pump can leak as you asked, but looking at the female o-ring/seal port at the tranny to receive the
electric pump, I doubt it can leak inside, unless there is a crack somewhere. Its a machined block and not using any kind of pipe as receiver.
Looking at the videos, I think that item is a big gasket itself. I suspect that the leak in my case is on item 30. Which is a pain since not only you have to remove the tranny from the car but open it up since the oil pump is assembled from the inside. There's an outer seal that could be the cause as well but that one is in contact with the TC axle and I suspect that if that was the case the TC would have oil on it.
If item 30
Clean the leak first , verify tranny oil fill level at tranny oil 45C temperature.
If indeed overfill , get it to proper fill by draining at 45C and you do not need to kick out the plastic oil level snorkel anyway.
If under-fill, its hard to guess by how much, but you can always inject more tranny oil and let it drip out.
41,000KM but you don't mention in your signature, the car is model year 2014 or 2015 ? , you best post that info as some wiring is different for 2015 year model.
I assume if you are the 2nd owner ( not 3rd ), and 1st owner was maintaining the car well, at its 5th year or by 2019 / 2020 if a 2014 / 2015 car, the tranny oil would be replaced.
I do not know what is the service duration for tranny oil they use in Brazil, in Indonesia they use 5 years or 75,000KM.
I've already cleaned everything and will monitor now. Unfortunately I don't have the means to raise the car in my garage in a leveled plane to check the level, but the dealer got me an appointment next week to investigate. I'll ask them to re-check the level since there was some oil coming from the breather valve. I just hope it's nothing more them that...
My car is a 2015 (Delivery date from the factory: Jan 2015 - YOM 14/1) and its first registration in Brazil occurred in June 2016 (more then a year between the import process from Germany and the time it seated at the dealer...). I'm the second owner but it was maintained by the same dealer since new so the dealer shop manager gave me the full history of the car. The assist plus computer was reset`ed when the car was delivered in June 2016 when the car was de-preserved for delivery, hence Assist Plus only called for the tranny fluid to be replaced when it underwent its March 2022 service. I found it odd that the dealer can reset the Assist Plus computer for delivery like that but apparently there's a MB procedure for that and a de-preservation process to be follow.
The previous owner declined the service and listed the car for sale Dec 2022. I bought the car in June 2023 and since the tranny oil was an year overdue, this was the first thing I had done in the car. Transmission works great, doesn't slips, had no leaks (at that time) and between March 2022 and when I bought it there was only 1.500 km in the odometer, so it didn't scarred me that the tranny oil service was overdue.
For Brazil, the manual calls for 5 years or 125.000km for the tranny oil, whatever comes first.
5 years 125,000KM, that is way too long if you want to keep this another 12 years to its 20th Bday, even if your traffic jam is say only 1/3 as bad as mine.
My car is 20 - 22K M/H average speed I am getting. So in terms of my low mileage, all my oil exposure to heat is equal to about 300-400% more to typical US cars which has much higher average speed.
You can use the instrument cluster engine hour reset feature, that is what I like using for 200 hours engine oil life or 5,000KM and now is 6-9 months only, no more the 12 months.
I do 2 years maximum or 20,000KM for tranny and DIFF oil. My 2 years max distance is approx 12,000KM if I do Jakarta-Bali-Jakarta run, otherwise under 5,000 KM a year.
20,000KM on my tranny oil is 900 to 1,000 hours being "cooked" already, hence I set 20,000KM. 2 years is simply I do not like any oil to be in my car longer than 2 years.
I want tranny to feel and behave as virgin as possible with least contamination trapped at the solenoid wire mesh strainer.
It is cheaper I spend on this tranny oil change protocol and hopefully at 20th car Bday, I do not yet need to replace any solenoid and the like.
My mileage by then would probably be max at 100,000KM if I am lucky to be able to do more long distance run each end of year.
This is probably the clutch ferro metal based material , the normal wear n tear on the tranny, which the magnets will catch.
The non ferro particles the tranny oil filter will catch them well...I hope .
Anyhow, I use the simple % rule.
If filter can trap 99% of typical contaminant size, the balance of 1% is free to roam.
1% of 100,000 particles is less damaging than 1% of a 1,000,000 particles count.
So sooner tranny oil change is a mechanical win for me, as particle counts will build up with mileage.
Here is a better wider angle tranny images for your use to help visualize your discussion with MB tech
I suggest you minimum get a Quick Jack ( 50cm max lift ) or something small too but can raise to 1 meter height.
You like cars a lot it seems and love to DIY.
I agree, 125.000 km just seems way to much. Maybe be for Europe or USA. With my previous W204 I replaced the tranny oil every 5 years. I usually only do 5.000 km per year so it wasn't a lot of milage involved.
I really need to get a better jack or lift system. Could never find anything like the Quick jack in Brazil and importing rules here are just crazy. Today, whenever I work under the car I use some ramps and drag myself in the floor as they don't give enough clearance to use a cart.
I'll keep you posted next week how it goes on the dealer.
Just to update everyone - I've cleaned my transmission last week and them drove for about 80km back and from the airport as I had a trip schedule. After that, there was a slight seepage on top of the flange of the engine small oil pan as there was still tranny oil coming from the drain hole that exists between the bell housing and the engine (blue arrows on the picture from S-Prihadi). Took the car to the dealer that replaced the tranny oil about 1.000km ago and they had my car for 3 days. They adjusted the oil level, cleaned and tested it a bunch of times. They said it was mostly left over oil that felt inside the bell housing from when they drained the torque converter. Apparently, they drain the TC from the side hole (with the black retangular plastic cap) instead of removing the aux electrical pump and that really would make a mess inside the bell housing.
Not sure if I'm buying their explanation but I'll monitor this closely for the coming months. If it was overfilled it could certainly explain a lot.
OK, lets hope it was simply that : They said it was mostly left over oil that felt inside the bell housing from when they drained the torque converter. Apparently, they drain the TC from the side hole (with the black retangular plastic cap) instead of removing the aux electrical pumpand that really would make a mess inside the bell housing.
They told me mine didn’t have a drain plug for the converter. My aux pump showed no signs of ever being removed. So disgusted with shops that refuse to do proper maintenance. Yes, that especially includes the dealership. They would rather you buy a new car and save them from having to actually do some work.
Shops (dealers or independents) will usually take the path of least resistance unfortunately. There is only one MB dealer in my city (which is also the Porsche dealer) and my experience with them is not the best. They tend to overlook issues and perform nothing more them basic maintenance required by WIS unless there's a customer complaint or is basic wear itens such as brake pads, rotors, etc. I suppose they act like that to avoid increasing the ownership cost of the car but it's frustrating for people that understand a little of their car maintenance.
However, I've been frustrated by independent shops as well. And apparently changing the tranny oil is my personal curse. With my W204 I had an independent shop do it and when I got the bill I've questioned the oil they used (236.14 instead of 236.15). My car back them had the ECO and reduced friction options on the datacard and I was positive they had to use the 236.15 oil but the guy in the shop was adamant that red fluid had come out the tranny and that is why he filled with 236.14 oil (first change ever and I had that car since new). So I decided to not stress myself and took the car to a transmission specialist shop to have it flushed and replace the oil and filter again. One moth after the second job, I've noticed seepage on the tranny oil pan... went under the car to inspect and found that the gasket was "bitten" in the forward section. Took the car again to the second shop to have the gasket replaced and, just to be safe, took my tools and personally torqued on all the bolts and inspect everything before they closed.
The solution apparently is getting a home lift and doing everything myself. I just have to convince the wife of that...
Last edited by Andre Cateb; 09-29-2023 at 10:48 AM.
They told me mine didn’t have a drain plug for the converter. My aux pump showed no signs of ever being removed. So disgusted with shops that refuse to do proper maintenance. Yes, that especially includes the dealership. They would rather you buy a new car and save them from having to actually do some work.
It certainly has a plug on it... The proper hay to drain it would be either removing the aux electrical pump and letting gravity do its thing or (I suppose) you could use a special fitting and drain it trough the bell housing side inspection port. To be honest, I feel like removing the aux pump might actually be easier and would add only the cost of the o-rings to the bill.
The other option, Mercedes Source has a kit, it doesn't flush, but moves clean fluid through cooler and converter so not to force any settled debris into valve body causing issues, but you end up with new fluid into entire system. At least I am going to go this route.
Expensive lesson, but a learned one not to be repeated.
Just to update, it's been a month since the dealer cleaned and corrected oil level in the transmission and no further leaks. I went under the car to confirm and is all bone dry.
Do these trans have a vent somewhere? I know my manual trans has a vent which if I overfill the sloshing around will cause some to leak out or if the vent gets stuck open which happens. Not alot but after 200k miles or so it builds up.
Do these trans have a vent somewhere? I know my manual trans has a vent which if I overfill the sloshing around will cause some to leak out or if the vent gets stuck open which happens. Not alot but after 200k miles or so it builds up.
Yes, the automatic transmission have a breather valve on the top, close to the junction of the bell housing and the transmission body. Part of the leak I had was apparently coming from it.
Yes, the automatic transmission have a breather valve on the top, close to the junction of the bell housing and the transmission body. Part of the leak I had was apparently coming from it.
Wanted to point out my manual trans is in my ram truck but ironically its a MB transmission (G56). Atleast it sounds like it all got fixed good.
Nice to see it was solved and I appreciate your update on your issue as well
Yes, if not the best , it's one of the best transmissions ever made . Torque Convertors rules
Happy Driving
09-19-2023, 08:25 PM
and that really would make a mess inside the bell housing.
