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

SL/R129: downshifting problems

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Old Oct 3, 2005 | 03:31 AM
  #1  
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downshifting problems

Guys

I have a 93 300sl with 68k miles. I have owned the car almost 5 years. During that time the tranny seems to have a mind of its own when it comes to 4th and 5th gear. Car runs and shifts great most of the time. It has a 5 speed automatic. It goes right into 5th spot on most of the time. However on occasion it will either not shift into 5th when it should or will downshift from 5th to 4th when it should not. I have been on the freeway doing 80 or 90 mph at cruise not accelerating and had it downshift to 4th. This happens fairly regularly. It follows no pattern however that will allow you to demonstrate this to a mechanic when you need it to. Sometimes it behaves for days without acting up. Car has been dealer serviced its whole life including tranny. I have been told that certain years of the 300sl from 90-93 had a weak design that causes this. Anyone out there with any knowledge of this occurence?

thanks

Ron
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Old Oct 7, 2005 | 01:32 PM
  #2  
Pigzmickey's Avatar
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From: Adelaide, Australia. Formerly Bristol, UK.
1998 SL 600 ///AMG. 1997 SL 320. 1999 SLK 230K. 2001 BMW R850.
Have you thought about getting the gear box chip remapped?
Just a thought!
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Old Oct 8, 2005 | 04:39 AM
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dafi129's Avatar
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From: Byblos,Lebanon
SL 55 , Infinity FX37, Aprilia Caponord Rally
I own a 93 300SL 24V with a 4 speed auto..
Apparently the 5 speed auto operates electricaly and hence is known to be problematic...The 4 speed autos are bulletproof..and so simple in design..
The only down side is high revs at high speed...Here in my country,many merc owners change from 5 to 4 speed autos...no maintenance except oil
and filter change at 20.000KM.A fitted 4 speeder here costs $300..recond..
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