RPM drop when shifting to drive or reverse

[Ottonoordraven]

Hi everyone

I have a 230 SL with automatic transmission
Even though the engine run nicely on idle ,
I have some issues with the performance of the engine  and transmission

1. When in Park or Drive it idles at around 850 to 900 RPM, when I Shift to
drive or reverse the RPM drop to 450 rpm
2.Shift up at very low RPM approximately 1800 RPM

What do you think should I do?

[stickandrudderman]

I think you should read the tech manual. everything you need to know is there.

[Cees Klumper]

Search for Constant Speed Solenoid. It's part of the linkage tour, restriced to full members, but in the forums themselves you will also find lots of useful information.

[Shvegel]

Search "Three position solenoid"  I am not sure if your car has one as it might just be the later transmission but if it does it adjusts the control pressure of the transmission depending upon throttle position.  If the linkage of the three position solenoid is stuck which is common it will not drop the control pressure and the engine will bog at idle in both drive and reverse.  If your car has the solenoid it will be located under an oval shaped cover beneath the carpet on the right side of the transmission tunnel.  Clean it and lube the linkage.