Driving my sons 89 240dl the other night and noticed the arrow light came on at some point, and the overdirve is not working. Pushed the button on the automatic gear selector and nothing happens, restarted the car and still doesn't engage overdrive. The car runs fine, but doesn't shift into 4th., or overdrive. We've only put about 600 miles on her since we got her in Feb. I need to get a bentley book, but the car has been very well taken care of from the original owner and haven't had any problems so far. I've got the questions below.

1. How does the system operate? Once the button is pushed, is it vacuum activated?
2. Is the switch supposed to click on or off? Mine just pushes in then springs back, no click
3. What parts are involved? I don't think we lost any gears, just something is not engaging.

 

no click on the button.
Trans is a 3 speed with electronic overdrive for the auto's (probably an AW70). Manual M46 have a 4 speed, with electronic OD, some only have 4 speed. M47 is the 5speed.

It is either the button acting up or it is the relay. or could be a bad OD solenoid.
This is for a 740, but it is the same basic ideas:http://www.vcoa.org/700-900-faq/Tran...OverdriveRelay

get the bentley book for better info....

wait for the experts to get on....

 

I have been chasing OD problems on our '87 for years, finally decided to do away with the lockout feature by modifying the solenoid per the article in the link provided by TIPSP. From my experience if the button does not make the arrow change state and the fuse is good, change the relay ($50). If the arrow changes state when you push the button and the fuse is good, the solenoid is the culprit.

Like the article says, if you modify the solenoid it will be a four speed automatic all the time. The only drawback I could see is maybe if you were towing a trailer or?

Lou

 

After reading your post again, if you don't have any blown fuses I would bet changing your overdrive relay would fix it. Remove the glove box and it is on the left laying on its side.

Lou

 

Thanks for all your help, would the fuse be in the fuse panel located on the drivers side next to the door?

 

Nevermind, found it, it does have a blown fuse. Can I buy these type of fuses from Autozone or replace it with a glass 8a fuse? Also, I've got to track down what caused it to blow.

 

Fixed, Oreillys carries european fuses. Thanks for the help.