moquinn06

Hi new to the forum and MBZ ownership. I just purchased an 06 R350 with 73k 4 days ago from a Dodge dealership. I took the car for an extensive test drive and had a pre purchase inspection completed through an Indy MBZ shop and it passed with flying colors. I live 150 miles away from where I purchased the car and the car drove great all the way home. The next day I was on an incline getting ready to pull out into traffic when the car rolled backwards while in drive. I thought it was strange but pulled out anyhow. About a minute later the car seemed to "slip" into neutral. The RPM's were increasing but the car wouldn't accelerate. I pulled over and turned the car off and after restart there was no evidence that this ever happened. Since then, there has been some form of this happening every day although not as severe as the first time. I am extremely concerned as this seems very unsafe. Also a bit discouraged since I didn't have the option to purchase an extended warranty. I have researched a ton and found several different possibilities. Has anyone else experienced this issue and if so, what was the fix. The car isn't throwing any codes through a generic scanner and like I said I had a pre purchase inspection done that should have checked for any stored codes. I just forked over a lot of money to buy the car so did I just get screwed or is this nothing to worry about? Thanks in advance!!

starbound01

Our R500 did something like this quite a while back. My wife was leaving the store and put it in R; the car didn't move. She tried D and R a few times and couldn't go backwards or forwards. She shut the car off and restarted it and no problem. Did this a couple of times over the week. to the shop it went and they replaced the transmission control block or somethign like that. It's a $2500 repair if memory serves. If you read the forum, its a common issue and is covered under the extended warranty if you get that. Don't know if there is a recall on it or not. Maybe someone here knows more about it.

Since you are new to the car. I think the R350 has a suspension compressor; replace the relay. $20 at the dealer, takes 2 minutes, and may prevent the need to replace the compressor at about $500 if you do it yourself. Cheap insurance. There are lots of write-ups about the issues with the R's. Also, I am always nervous working on the car because mistakes are expensive to deal with. But nothing I've touched is rediculous to fix (granted I did not replace the broken drive shaft - that is a $3K repair from the dealer.. You just need a little more patience and not brute force stuff. Good tools helps.

moquinn06

I forgot to add that the battery went dead on Friday night and Saturday is when the erratic shifting began. This morning I took it to a parts store to have the battery tested and they told me the alternator is bad. I called the dealership I purchased the car from and they are going to cover the repair! I am keeping my fingers crossed that this is what is causing the issue. Thanks for the info.

rostrom

It sounds like it may be a bad conductor plate. My wife had similar problems in her SLK280 that has a similar tranny. If the new alternator does not fix the problem take it to an MB dealer. Mercedes apparently does not sell the conductor plate part to independents, so they will only be able to replace the entire transmission (which costs $6k). The conductor plate fix cost us $1,200 but allowed us to skip a tranny service (which costs $500). While this would stink to have to do on a car you just bought, it will result in a car you can enjoy for a long time.

crs72c

I second the valve body/conductor plate. I had similar issues when I got my R350 but it was fully driveable once I restarted the car.

Did a red or white battery light appear in the display?

supernsx

^^this.

moquinn06

Ok sorry for the delay in response. I took it to my indy mechanic and he diagnosed just as you all said, the conductor plate. It was sent to the dealership to confirm diagnosis. She will be fixed next week! I got the dealership I purchased it from to split the cost with me and Mercedes discounted the job 10% after I contacted corporate. My dealer charges $1500 plus tax but I should only end up paying around $500 which like was mentioned I would have to pay for a tranny service anyhow. It is actually better that it happened right away since the dealership is chipping in. I am hoping to be problem free after this. I had an Audi A6 before this and I loved it so I am hoping for the same experience with Mercedes. Thanks for all the advice!!

moquinn06

Today I also had the check engine light come on and the codes were p0717 and p0718. I know this are both transmission related but I am concerned about the valve body. What are the odds that it could be that also? I am just afraid that I will get it to the dealership and they will find more issues!

rostrom

Those are tranny sensor codes:
P0717 Input/Turbine Speed Sensor Circuit No Signal
P0718 Input/Turbine Speed Sensor Circuit Intermittent

So some sort of bad sensor. While I have no idea if it is related to the conductor plate, I would bet that it is. I say just get the conductor plate issue fixed (awesome that they are covering a good part of the cost) and see if these codes return.

supernsx

if you do a Google search and those two codes can be related to your conductor plate issue.

moquinn06

Thanks supernsx, I saw where it could be either the conductor plate or the valve body. I also have read where the dealership diagnosis one and when they go in to repair they have to replace the other also.