overdrive problems sl300

[gireaud]

some times my transmition do not take overdrive or fifth gear and some time is ok, everything else is working fine. Have someone any experience on this matter. please help.

[bobterry99]

The overdrive is controlled by an electronic module located in the area of the ABS and CFI controllers under the hood. One of the inputs to this module comes from a switch inside the shifter housing. The switch is closed when the lever is in "D" and opens when it is moved to "4".

The shift contacts can get dirty and cause the intermittent operation you describe. If you remove the center console and the shift lever, you can partially disassemble the shifter housing, remove the switch, and clean its contacts. You probably out to have the R129 Tech DVD or Mercedes WIS software available for instructions.

[waybomb]

Mine does the same thing. Just haven't has time to take apart the console. Plus, I don't know how!

I can get it to engage by moving the shift lever to the "4" spot, then lightly slapping it over into the "D" spot.

[gireaud]

Originally Posted by bobterry99

The overdrive is controlled by an electronic module located in the area of the ABS and CFI controllers under the hood. One of the inputs to this module comes from a switch inside the shifter housing. The switch is closed when the lever is in "D" and opens when it is moved to "4".

The shift contacts can get dirty and cause the intermittent operation you describe. If you remove the center console and the shift lever, you can partially disassemble the shifter housing, remove the switch, and clean its contacts. You probably out to have the R129 Tech DVD or Mercedes WIS software available for instructions.

bobterry99, i really appreciated your help, i dont have the tech dvd or Wis software, please tell me where i can have one of those, so i can order one, i live in Venezuela. Thanks again.

[gireaud]

Originally Posted by bobterry99

The overdrive is controlled by an electronic module located in the area of the ABS and CFI controllers under the hood. One of the inputs to this module comes from a switch inside the shifter housing. The switch is closed when the lever is in "D" and opens when it is moved to "4".

The shift contacts can get dirty and cause the intermittent operation you describe. If you remove the center console and the shift lever, you can partially disassemble the shifter housing, remove the switch, and clean its contacts. You probably out to have the R129 Tech DVD or Mercedes WIS software available for instructions.

hi bobterry, i did switch cleanned, but the problem continue, still there. do you have an other idea, where i can look to?

[waybomb]

gireaud

How do you get the console wood off? I found how to take the entire console out, but the video started with the wood already off. I was going to do this today but couldn't figure it out.

Thanks
Fred

[waybomb]

Well, thanks everybody.

I pulled the entire console out and removed the shifter from the car. I popped the cover off and removed the switch.

The switch is closed when in P, R, N, or D. When the shifter is moved to the gate, ie, 4,3,2, the switch opens via a small mechanism.

I carefully disasembled the switch. It was clean, but I took an old points file I had and cleaned the contacts.

While I had the console apart, I cleaned 16 years of spilled coffee and found about 50 cents.

I put it all back together, and overdrive now seems to work as it should. I'll find out tomorrow when I'm on the road for a while.

So, it took me a liesurely 3.5 hours, so, I made about 15 cents an hour.

Again, thanks for the help!

[bobterry99]

Originally Posted by gireaud

hi bobterry, i did switch cleanned, but the problem continue, still there. do you have an other idea, where i can look to?

I would read diagnostic codes. Actually, I should have suggested this FIRST. You read codes from socket #13 of your diagnostic connector. If you need help with doing that, send me another email.

[waybomb]

Could the gate mechanism be snafu'd?