My ml320 keeps acting up and the dealer doesn't find anything wrong.Sometimes when I go somewhere and shut my truck off and then start it back up to leave,it won't shift up.It wants to remain in first gear.So I then stop completely,rev the motor up then let the rpms dy down to at least 7000 and shift real quick to drive ,then when I take off it shifts up just fine.this only happens after the car is warmed up.Likegoing to the store and then leaving.Could this be the EGR valve.The dealer checked it and said it was fine but it store a code for the egr valve.

 

Not sure if it is related but I had a similar problem. My Ml320 would not up shift past second gear (limp mode) this only presented a major problem when getting on a highway or trying to accelerate from a stop light the tac would go up to 5 to 6 thousand rpm. I took it to the dealer several times while still under warranty but they could never get it to replicate the problem. It was very infrequent at first but it became much more of a normal occurrence and then it was out of warranty. i then started noticing it would lurch into gear and then the next few time i would drive it seemed to occur. I did notice that if i let the car sit shortly after start when the engine rev's up and let it warm up until the the tac drop it didn't happen as much. In the end i was finally getting check engine light and i had to replace transmission module chip which is not cheap. on a side note once this started to happen more frequently i started to notice a rattle and i had a cracked head as well the service manager from the dealership thinks this could have been caused from high Rpm when the ML would go into "limp mode". Good luck

 

my ML320 had i think the exact same problem, i was on my way on a trip up to canada from texas, and it turns out someone had been pushing buttons and the low range button was hit. i took it to the local mercedes dealership in michigan and they had to take out 2 chips from the car and replace one for fairly cheap around 200$ i think, and they wanted 800$ for the other, but they claimed you dont need both.... this is just what my mom, ( the previous owner ) has told me, but mine runs fine now.

 

It's not the EGR valve, it's the transmission.

You would rev up above 7,000 rpm when you were stopped and then let it down to 7,000 rpm and put it into gear? Sheesh! What ever was wrong you undoubtedly made it worse by doing that.

 

(I don't know much about theses cars)
But it def. sound like a transmission problem. Have somebody check for metal in your tranny pan...

And I hope you ment 700rpm and not 7,000


regards,
leonardo