2005 CLK 500 transmission issue

[Mr57]

Hi all,
When I drive on the freeway and then exit, my transmission gets stuck in high gear until I shut the car off, then goes back to normal operation.
While driving in stop and go traffic, it shifts and works great, the car has 82,000 miles. What could cause this issue?

[engatwork]

Has the transmission ever been serviced - fluid/filter change? Can you get all of the cars fault codes read?

[Mr57]

Yes, the transmission was serviced at 70,000 miles, I'll see if I can get any codes.

[engatwork]

It should have a transmission fault code.

[bigpanda16]

This has happened to me twice on 2 different 722.6’s and both times it was the conductor plate, once swapped, they returned to normal operation.