OBD code 700
 

Friend of mine's 99 ML320 is throwing an error code 700, Transmission Control fault. What could be wrong with the tranny?

Any DIY thingies I can do? The stealership wants $1700 just to do a test. Also there is NO transmission dip stick, how can one check the fluid level and quality of fluid, color/burnt smell etc?

Many independent shops can read transmission codes that will help with diagnosis.
That should be the starting point.