1991 Mercedes Benz 230te • 220,000 miles

My Mercedes has recently developed a slight problem with its reverse gear. When fisrt starting it in the morning when it is still cold reverse you can select reverse gear. Once the car has warmed up a little and you have driven a small distance i.E. 3 to 5 miles, then when you select reverse gear it will not engage. Once stopped and cooled down for about 45 mins to a hour you can then start the car and select reverse gear and it will once again engage. What can be causing this problem.
January 12, 2012.

Check transmission pump output pressure when in reverse.

Jan 13, 2012.