One of my customer have 2000 E240, and he complain the transmission .
The transmission doesn’t change to 3rd or 4th gears, he turn the car off for 5 minutes then started again and it will work perfect for only 10 mints .. then the problom will back after few minutes !
The fanny part , he take the vehicle to The dealer , the customer service counter told him that the transmission need to change !! with out any check .
I think the problem coming from sensor or TCM . but I don’t know how to find out .
is tripping it into limp mode.If it stayed in 3rd engine system related,since it keeps skipping back into low gear trans is trying to tell you something.Do you have a scanner to check codes?Have you tried a battery reset to see if you can renew the communication of the tcu the ecu and the ignition module?
Keep us posted.