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Old 09-23-2008, 10:12 PM
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Graham Graham is offline
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Join Date: Nov 2004
Location: Ontario, Canada
Posts: 4,391
Originally Posted by Tom Drew View Post
Hi Graham,

I had to replace both the kickdown switch under the accelerator and the solenoid at the trans. to restore proper kickdown. Check the kickdown switch under the accelerator with a voltmeter by hooking the + lead to the power wire at the trans solenoid, and the negative meter lead to ground. Turn on the ignition and have a helper floor the acclerator. You should see 12 volts at the meter, indicating that power is arriving at the solenoid when the kickdown switch is activated. If not, move over under the driver floorboard to the kickdown switch terminals, see if you have 12 volts feeding the switch. If yes, the the switch is bad and needs to be replaced. If no, the fuse is blown or there is a break or short in the power wire to the kickdown switch.

When I removed the solenoid from the trans, a small amount of fluid leaked, but I stopped it up with a correct-sized plastic hole plug until I installed the new one. Save the small aluminum sealing ring and note where it goes when you remove it, so when you install the new one it will be leak-free. Solenoid is not available from MB. Did some sniffing around and was able to source one from Sun Valley Mercedes Dismantlers, Sun Valley CA. for $50.00. Installed it and I'm back to proper trans operation with kickdown on hard acceleration.
Thanks Tom,

I have been tied up on other things, but had a quick look and see there is a plug that I can use to check that switch is working. I have also had a look at the solenoid connections and it should be easy to check.

Now, all I have to do is find time to check it out!
85 300D,72 350SL, 98 E320, Outback 2.5
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