SL-Class (R129) 1990-2002: SL 280, SL 300, SL 320, SL 500, SL 600, SL 60 AMG

SL/R129: 1999 sl500 shift module

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Old Mar 7, 2021 | 07:04 PM
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E=MC^2's Avatar
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W203X2 w201X3 W208 W129
1999 sl500 shift module

Hey all, my 99 sl500 had an issue where it would not shift out of 1st. I did not figure it out until it was dark. the shift module lights were not coming on. when shifting to D. I have to jiggle the shifter or find the sweet spot for the light to come on and for the transmission to receive the electrical signal from the shift module.

I have replaced my shift assembly with a used Ebay unit
.. it does the same thing. is there a write up or video on how to repair the shifter?

Thanks-Brian
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Old Mar 7, 2021 | 09:01 PM
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sushipaste's Avatar
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1999 SL600
Disconnect and reconnect battery, (dont forget to resync windows and esp lights) and see if that fixes it. If not perhaps STAR diagnostic can reveal codes that need clearing
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Old Mar 7, 2021 | 10:14 PM
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W203X2 w201X3 W208 W129
I should rephrase this. I believe the issue to be the shifter. the 722.6 has an electrical shift assembly. I first thought my issue was the transmission itself not shifting. it's truly within the shifter assembly. it internally is not registering that it is in gear. Not lighting up " D " and not sending the signal to the TCM. when the selector light does come on when in the "sweet spot" the transmission functions normally. when the shifter does not register the gear and the light does not come on even tho it's in gear car takes off in second and will not upshift.

Anyone else experience this? can I take apart the shifter clean it? any tips? I have tried to replace it with a used unit unfortunatly this part does the same thing... maybe try another used unit?

Last edited by E=MC^2; Mar 7, 2021 at 10:16 PM.
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Old Mar 7, 2021 | 10:57 PM
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You probably have trashed shifter bushings then. Get them checked out. You should still try what I previously suggested. Also take a look at the tcm for fluid intrusion and look at the pilot bushing for any wetness
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Old Apr 24, 2024 | 06:23 PM
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R129 320SL 98
Did you end up resolving this issue? Please advise
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Old May 9, 2024 | 01:41 PM
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1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
shift issues

I would start with inspecting the electrical plug connection on the passenger side of the transmission just above the tranny pan corner. Once you removed the plug look for fluid. This is a very common failure.
Have you kept up with tranny fluid & filter changes?
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Old May 16, 2024 | 04:16 AM
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BYD SONG
Originally Posted by E=MC^2
Hey all, my 99 sl500 had an issue where it would not shift out of 1st. I did not figure it out until it was dark. the shift module lights were not coming on. when shifting to D. I have to jiggle the shifter or find the sweet spot for the light to come on and for the transmission to receive the electrical signal from the shift module.

I have replaced my shift assembly with a used Ebay unit
.. it does the same thing. is there a write up or video on how to repair the shifter?

Thanks-Brian
Hey Brian, that sounds like a frustrating issue with your SL500's shifter. There are a few potential culprits - it could be an issue with the shift linkage, shift module, or even the transmission valve body. I'd recommend checking for any technical service bulletins or known issues first.
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