SL/R230: Transmission problem
Thread Starter
Junior Member
Joined: May 2013
Posts: 16
Likes: 2
From: East Tennessee, Northern California
1984 380SE, 1986 560SEC, 1988 560SEC, 2005 S430, 2005 SL500, 2012 S550 4matic
Transmission problem
I have a 2005 SL500. It has 57,000 miles. After 10-12 miles driving, it becomes stuck in seventh gear. I can stop, shift to park, and pull out and it is stuck in first gear. I can shift into neutral while it is rolling and back to drive and it is stuck in whatever gear is appropriate for that speed. If I stop, turn the car off and restart, it works fine for another 10-12 miles and then back to the same problems. No warning lights are on the dash. So I'm assuming it is not in "limp" mode. Anyone have this experience or have info on this problem?
Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
Probably the conductor plate in the gearbox. Much discussion on this topic online.
https://mbworld.org/forums/sl-class-...-shifting.html
You will need to get the codes to confirm it; there are several powerful low cost hand-held scanners on the market that can do this. Many or most people reading this, even competent home mechanics, would be getting a specialist or an MB dealer to do the job.
https://mbworld.org/forums/sl-class-...-shifting.html
You will need to get the codes to confirm it; there are several powerful low cost hand-held scanners on the market that can do this. Many or most people reading this, even competent home mechanics, would be getting a specialist or an MB dealer to do the job.
Thread Starter
Junior Member
Joined: May 2013
Posts: 16
Likes: 2
From: East Tennessee, Northern California
1984 380SE, 1986 560SEC, 1988 560SEC, 2005 S430, 2005 SL500, 2012 S550 4matic
Thanks Tom. I have the icarsoft scanner and will see what it says in the next day or so. Although, as I said, no warning lights on dash. I too suspect the conductor plate and I'm wondering about the mail in services for repairing the conductor plate. I meant to ask that in the original post. Has anybody out there used one of these services such as circuit board medics for the repair?
Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
That's right, you won't get a message or a light on the dash but the system will store the codes. This was the only time I've taken my 500 to the dealer; it was expensive but they replaced the valve body too and didn't charge me for it. They serviced the transmission too. But charged for that.
That was 2017 and the fault has not returned so I think the new conductor plate has the fault rectified.
I wouldn't tackle it without a hoist.
That was 2017 and the fault has not returned so I think the new conductor plate has the fault rectified.
I wouldn't tackle it without a hoist.
Thread Starter
Junior Member
Joined: May 2013
Posts: 16
Likes: 2
From: East Tennessee, Northern California
1984 380SE, 1986 560SEC, 1988 560SEC, 2005 S430, 2005 SL500, 2012 S550 4matic
Thanks so much for the advice. I'm trying to do anything I can to avoid the local dealer here because of several bad experiences in the past. I'm lucky enough to have a car lift here at home, so I'll either give it a try at home or find someone other than the dealer.
Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
Sure. I'd tackle it now with what I know now, and a hoist. Getting it in and out doesn't sound too hard but reading through this:
https://mbworld.org/forums/sl-class-...removal-2.html
it seems if the electroplate is warped or damaged you won't be able to repair it. A new unit must be coded by the dealer, pretty much, unless you're handy with reprogramming EEPROMs...
But if your codes indicate a failed speed sensor you can probably replace that sensor on the electroplate yourself. I'm curious why MB of Melbourne here replaced my valve body and didn't charge me for it though.
https://mbworld.org/forums/sl-class-...removal-2.html
it seems if the electroplate is warped or damaged you won't be able to repair it. A new unit must be coded by the dealer, pretty much, unless you're handy with reprogramming EEPROMs...
But if your codes indicate a failed speed sensor you can probably replace that sensor on the electroplate yourself. I'm curious why MB of Melbourne here replaced my valve body and didn't charge me for it though.
Thread Starter
Junior Member
Joined: May 2013
Posts: 16
Likes: 2
From: East Tennessee, Northern California
1984 380SE, 1986 560SEC, 1988 560SEC, 2005 S430, 2005 SL500, 2012 S550 4matic
Handy with EEPROMs? I actually don't have a clue what that is!! 
Sounds like you got lucky with your dealer. Pretty sure that would never happen with mine.
Haven't pulled my codes yet but , there is at least one local independent shop that can do coding. Thanks again for all your help.
Sounds like you got lucky with your dealer. Pretty sure that would never happen with mine.Haven't pulled my codes yet but , there is at least one local independent shop that can do coding. Thanks again for all your help.
