CFH55

After a long hiatus away from the forum I finally have some free time to post. So I have a simple question, I understand the 3 modes the transmission in the cls55 has however I have recently had a strange issue when using the M mode. The transmission shifts fine in all modes, and just so it is known, I have changed the trans fluid and filter at 40k miles as should be done. But when I have been using M mode the car will without my doing revert back to full auto S mode. Is this supposed to happen, I feel like I am going a bit crazy because I could have sworn that once you place the car into M mode the car should stay in M mode until you switch out of it to C or S mode or if you turn off the engine it will not remember being in M mode and will automatically be in C or S mode when you restart. Basically the car goes into M mode allows me to shift and all that but it will then without my doing suddenly put itself into C or S mode. Is this right? Has anyone else had this issue? Thanks for the advice and I hope you all have a great weekend.

vvrjrlaw

First thing you want to do is scan the car for codes. And when you scan use a scanner that can look to the TCM because your transmission issues end up stored there. I'd also check the connector between the transmission and the TCM for any signs of leakage because it will wick up to the TCM and cause erratic operation and possibly damage ( if the fluid has any metallic particles in it). Post what you find if anything. Good luck.

PieRat

Did you ever figure this out? I have the same issue..