W202 1998 C280 Transmission problem - Please Help

Hi all.
let me say that the forum is very good.I apologize for the bad English that I have, because it is not my original language.This is my first post here in the forum.I have a MB W202 C280 Sport USA version M112 engine . a few weeks I have it stopped by a strange problem in the transmission.
Let me tell you to see if anyone can give me an idea of what might be.Few weeks ago the car did not perform the shifting and had a strange humming noise, but that happened only once. We took it to the mechanic and said it was an electrical problem and had cleaned the sensors and it works (do not know what sensors) . They also suggested we perform the change of the transmission oil.We made the oil change and after that the car no longer worked. But the strange thing is that if you run the car in the morning works perfectly for approx. 30 minutes making gear changes beautifully, after those 30 minutes stop shitfting and remains as in limp mode with that strange humming sound.I thought I had not sufficient amount of transmission oil but I have the meter to check. so I take chances and add 1 quart. more to test but does the same.once the vehicle is cooled again fully operational for 30 minutes.
Also the mechanic scan the transmission codes. He said that " ECM has code ID151 gear comparision incorrect and code ID 147 gear implausible or trans.slipping". Also the differetial pinion seal is leaking and needs a transmition mount.
Any sugestions what should I do???
Thank you all
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, October 8, 2012 3:47:22 PM UTC-4, snipped-for-privacy@gmail.com wrote:

If your Mercedes is a 202029 chassis it has a 722.6 transmission. Common problems are the electronic conductor plate atop the transmission valve body and the transmission control unit. The electrical connector at the transmission frequently leaks trans fluid into the trans wiring harness and eventually into the control unit. No easy diagnosis here. Take your Benz to the nearest Factory authorized Mercedes-Benz Dealer where they can properly diagnose the problem and give you an accurate estimate of repairs.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thank you for the reply,
I did the same thing what you have been told me and the estimate that the transmition it should be replaced... that will cost me aprox 5000$ :/ What now?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.