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We have a 2008 R350 which has 58k miles on it. I just did the following to it and have started to have severe transmission problems and I have no idea what I did wrong.
1) I replaced the cabin filter
2) I replaced the air filters
3) I replaced the engine oil / filter with 8.5 quarts of M1 0w40
4) I replaced the auxiliary battery
5) I put a gas additive to clean the injectors
6) I reset the transmission learning (hold gas pedal down method)
7) I has an alignment done at Pep boys
8) I rotated my tires (one of the two front tires has 3/32nd on it while the other has 9/32nd on it).
Now, for some odd reason, my transmission is going crazy.
The symptoms are:
1) When I come to a stop i hear a clunk and a surge forward at speeds of < 30 mph. I noticed this for the first time after doing the oil change and before the transmission adaptation reset.
2) After two more short trips (<1 mile each), my 1st to 2nd is slipping! I didn't want to let it rev too high, so I used the paddle shifters to shift forward. Since then, the transmission is clunking around like crazy.
It seems as the transmission is now shot completely as i've only driven 3 miles since doing all these services. It drove perfectly fine yesterday for 30+ miles of city driving.
Anyone have any idea what I could have done wrong? I followed the DIY oil change instructions which was pretty straight forward.
Update: I got a CEL while driving around some more. I took it to auto zone and the OBD2 came out with the following:
P0170 and P0173 which they're saying is the Mass flow air sensor.
Did I screw up the air filter install? How can this affect the transmission, or are the two completely unrelated?
I remember one thing which is that when I put the air filter cover back on, the metal clamp on the rear left came off and fell inside the engine bay. I couldn't find it on the floor so couldn't get it back on. Do you think this could be it?
How's the fluid level in the trans? Check the rubber hoses around the TB/MAF and valve covers, also make sure your airbox is seated and sealing correctly. Might be related but shouldn't be.
I don't know how to check it. From what I read, there is no dipstick. Do you know how I can check it?
And in this case, it would be insanely bizarre if the transmission issue went from 100% operational to nearly dead directly after doing my services and not having it be related. I am going to reopen everything and make sure it all gets seated properly. I don't know what to do about that clip that fell off though.
I don't know how to check it. From what I read, there is no dipstick. Do you know how I can check it?
And in this case, it would be insanely bizarre if the transmission issue went from 100% operational to nearly dead directly after doing my services and not having it be related. I am going to reopen everything and make sure it all gets seated properly. I don't know what to do about that clip that fell off though.
Agreed, it's highly unusual. I added to my post after you quoted in regard to your "MAF" codes. I don't put much faith in generic code readers, they miss many things on the MB cars.
Trans fluid level is checked with the vehicle level and running from the pan by removing the drain plug at a specified temperature and ensuring there's enough fluid for some to run out. If not it's filled through the pan using an adapter.
I really appreciate you helping me out on this. Its 8oclock here and i'm desperately trying to figure this out.
I just took everything apart again and here is what I found.
1) The silver clamp at the back wasn't really hooked on properly (i.e. no tension anywhere on it).
2) It looks like there was a plastic extension that broke off (see image below).
The clamp doesn't even reach the two hooks on the bottom picture.
This is probably why it is throwing the error. It is creating a vacuum/air leak. I am wondering if buying a new one will fix the transmission issue. Perhaps the computer is adjusting the trans shifting due to this problem?
Ok, I am an idiot. I just didnt press down hard enough. I got the clamp over the two hooks.
Unfortunately, but as expected, this did nothing about my transmission problem. It still clunks around and seems to slip btw 1st and 2nd.
The shifts also happen at higher RPMs. In the past, it used to shift at lower rpm's when accelerating. Now it does it at higher RPMs and usually just hangs in a lower gear when i let go of the gas rather than upshifting. I guess this is due to the transmission adaptation reset?
Could it also be my front tires? My front left after rotation is 3/32nd while the right tire is 9/32nd. A new one to replace the 3/32nd is literally in transit - bad timing for this issue!
One more question. Assuming the CEL was related to the air filter clamp not bing connected properly, and it is reset, will the transmission slipping/banging generate a new CEL code that I could read?
the seal between the air filter and the MAF is of no consequence really. The MAF reads the airflow even if it enters via an air leak upstream.
If you didn't touch the transmission fluid.. why would the level be of a concern all of a sudden?
Careful not to go on a wild goose chase.
Did you perhaps damage the MAF or connector?
Get a map and compass. face Stuttgart. kneel down and pray?
the seal between the air filter and the MAF is of no consequence really. The MAF reads the airflow even if it enters via an air leak upstream.
If you didn't touch the transmission fluid.. why would the level be of a concern all of a sudden?
Careful not to go on a wild goose chase.
Did you perhaps damage the MAF or connector?
Get a map and compass. face Stuttgart. kneel down and pray?
I am on a wild goose chase right now as you can imagine. I wont be able to drive the car until next weekend (it is a secondary car that my wife and I keep at my parents house since we live in Manhattan).
I don't think I damaged anything. I am not sure where the connector is, but I will check it next week if any of the connectors look damaged.
I want to reset the CEL and see if that error comes back now that I've properly secured the clamp.
I still can't get over the bizarre fact that just after I do these services the transmission goes from operational to dangerous.
If you noticed the transmission problem AFTER the oil and filter change and aux battery. Either you did something there or it it is completely unrelated.
How did you do the oil change? Did you remove the plastic underbody to get to the oil pan plug or did you use a vacuum extractor. How did you change the cabin filters? From the engine bay or did you remove the glove compartment? I think the ECU is near the glove compartment since a plugged drain on the cabin filter engine bay housing will flood back in to the cabin and ruin the ECU. Just thinking of what you may have touched along the way.
If you noticed the transmission problem AFTER the oil and filter change and aux battery. Either you did something there or it it is completely unrelated.
How did you do the oil change? Did you remove the plastic underbody to get to the oil pan plug or did you use a vacuum extractor. How did you change the cabin filters? From the engine bay or did you remove the glove compartment? I think the ECU is near the glove compartment since a plugged drain on the cabin filter engine bay housing will flood back in to the cabin and ruin the ECU. Just thinking of what you may have touched along the way.
Here is what I did step by step in time order as best as I can remember:
Saturday:
Drove the car on for about 40 miles with a mix of local/highway driving. I did not notice anything at all that would lead me to believe there was transmission trouble. I had a car with tranny issues before, so know how to spot them.
I drove home and started to do the following services:
Air filter:
- I removed four bolts plus the long pin that hold the strut brace in to be able to remove the air filter cover. I removed the air filter cover and replaced the two air filters inside it and then reinstalled it. I had not clamped it back properly as mentioned above, but subsequently fixed it after I got the CEL the following day.
Cabin filter:
- I removed the plastic cover inside the engine bay on the top left (when facing the engine). There were two spring clamps that held it in. I removed two filters and reinstalled it back to where it was and put the plastic cover back on.
Sunday: Engine oil:
- I pulled the car onto ramps, removed the plastic cover under the oil pan (perhaps 10 screws or so), removed the oil pan bolt to drain the oil, put it back in, filled it up with 8.5 qts of M1 0w40 full synthetic, replaced the oil filter (from the top), and put the plastic cover back on underneath.
Aux Battery:
- I removed the plastic passenger door sill, pulled the plastic footwell cover off (just in front of it that is on the side of the footwell), lifted the carpet, unbolted a few bolts to get to the battery, removed the battery (-ve first then positive), put in the new battery (positive first then negative), and reinstalled everything back
Gas additive:
- I added fuel injector cleaners to the car into the gas tank (chevron I think). Didnt think this was relevant, but just throwing it out there in case.
Transmission adaptation reset:
- I put the car in the On position (second click) without turning the car on, pressed the gas pedal all the way down for 30 seconds, turned the car off, let go of the gas.
After doing all this, I started driving to Pepboys to get an alignment, state inspection and tire rotation. This is when I felt the first thud when downshifting at the first traffic light by my house. I felt the thud once more before I got to pepboys (only about a mile away from my house only when coming to a full stop).
Once the tire rotation, alignment and inspection were done, I started driving home. Right away I noticed the slipping from 1st to 2nd, clonks underneath my seat got worse and were felt in every gear. This is why I think it is either something that went wrong with one of these services, or it is an insane coincidence that this happened.
Thanks for your help. I really appreciate this.
I called MB and they want 150 for a diagnostic. I am thinking of doing it next week although I am not sure I will get an answer other than just to replace the tranny. If this is the case, the car is going to the junk yard (or ebay perhaps). Such a shame for such a low mileage car (58k) that was never beat on (driving by old in-laws).
Hi there,
sorry to hear you having such troubles and was thinking that perhaps it could be unrelated to the work you did ...
Or it was just a catalyst for something that decided to finally start giving trouble...
As thought, perhaps the valve body / conductor plate may be causing the gears to act erractically.. the trans can be fine but it's controlled by the this piece of gear that apparently fails fairly commonly (on the 7G transmissions...).
I'm suspecting that this is my problem on my R500 and taking it to MB this wednesday... i don't have anything like what you're describing, more of a hard shift / jerk when slowing to a stop (like 2 to 1st)... And this only happens while the engine is still cool.
Best of luck with what you find, let us know if you get it back on the road
Hi there,
sorry to hear you having such troubles and was thinking that perhaps it could be unrelated to the work you did ...
Or it was just a catalyst for something that decided to finally start giving trouble...
As thought, perhaps the valve body / conductor plate may be causing the gears to act erractically.. the trans can be fine but it's controlled by the this piece of gear that apparently fails fairly commonly (on the 7G transmissions...).
I'm suspecting that this is my problem on my R500 and taking it to MB this wednesday... i don't have anything like what you're describing, more of a hard shift / jerk when slowing to a stop (like 2 to 1st)... And this only happens while the engine is still cool.
Best of luck with what you find, let us know if you get it back on the road
I've read about the conductor plate. I am going to take it in on Saturday to get a diagnostic done for $150. I will tell them what I've done to the car to see if that can help with the diagnosis. Good luck with your car tomorrow. How many miles do you have on it? Also, I've read that replacing the conductor plate sometimes wont work in the long run. I hope that's not the case.
My milage is at 122k miles... servicing has been always kept to date.
I spoke with my indy earlier today (20yrs on mercs only) and he knows the issue with these 7g's well.. he won't do just the conductor plate, he will only do both the conductor plate and valve body ... he said by the time you get there and remove the plate, you're already at 1grand, so for another 600 just do it all and be done with it
i'll see what MB says but there's no CEL lights and when the engines warm, it doesn't do the hard shift so i expect that they'll have to hold it overnight and diagnose ...
My milage is at 122k miles... servicing has been always kept to date.
I spoke with my indy earlier today (20yrs on mercs only) and he knows the issue with these 7g's well.. he won't do just the conductor plate, he will only do both the conductor plate and valve body ... he said by the time you get there and remove the plate, you're already at 1grand, so for another 600 just do it all and be done with it
i'll see what MB says but there's no CEL lights and when the engines warm, it doesn't do the hard shift so i expect that they'll have to hold it overnight and diagnose ...
Got it - good luck with that. Does the plate and valve body just prolong an eventual failure, or has it been proven to fix the problem?
Got it - good luck with that. Does the plate and valve body just prolong an eventual failure, or has it been proven to fix the problem?
Keep us posted on your car, too.
well ... instead of hijacking your thread, i started a new post on my R500 lol... outcome still pending but the initial reports are laughable (or hair tearing depending on how you deal with things)
But i did do some searching on the valve body / conductor plate and found this really interesting article ... http://www.mercedesmedic.com/must-re...nductor-plate/
and the only correction to the above is that mb ARE selling the vb/cp units to indies now... (they didn't use to)
On Friday, I called a local mechanic that I found on the forum to see if he could help me out. I told him what I did over the phone and he said that since I replaced my Aux battery, the transmission was in relearn mode and that I just had to drive it for a few cycles (drive, park, shut off, restart, etc).
I had my appt scheduled with the dealer on Saturday, so on Friday night I took it for a spin to Autozone to get my CEL reset (about 1.5 miles local driving). The transmission at first was a little rough, but nowhere near as bad as what I posted above. Downshifts were smoother and no slipping btw 1st and 2nd.
Autozone could not reset the CEL, but when I restarted the car to leave, it went off on its own anyway (as the clamp was now properly secured). The car continued to get better as I drove some more. I took it on the highway for a few miles, did some more local driving with periodic restarts in between and it drove perfectly fine.
I cancelled my appointment at the dealer on Saturday morning and spend some more time driving it around and it seemed to be back to normal! I went ahead and installed a new tire that I bought before these problems started happening and at the end everything is working well.
This is absolutely crazy as I was literally ready to get rid of the car. This could be a fluke, but it brings me some piece of mind that I didn't screw anything up last weekend.
09-24-2017, 06:14 PM
