C240 Transmission Control Problem?

My 2002 C240 goes into gear with a thud and won't upshift. As I suspect it's a problem with the transmission control unit/module, before I take it to the dealer, I was wondering if anyone knew where I
could get a new or rebuilt module if it turns out that I need one. Google doesn't turn up anything.
Thanks very much in advace.
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It is rarely ever the transmission brainbox. First thing I would do is change the filter and fluid and see what happens when you do so. Alot of time on newer car, this is all you need. There is no such thing is lifetime fluid... those who believes that will need transmission overhaul anytime after 100,000 miles.
On modern electronic transmission, it can be individual electronic part that go bad and dealer will just change that only part. Do you have any 'Check Engine' light?
http://silverstartransmission.com /
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Thanks a lot Tiger. Yes, I am getting a "check engine" light. What's up with that?
Thanks again
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