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Discussion Starter #1
Hi there

I have a trans leak in my 1989 500SEL. A couple of patches two inches square after a run.

All pan bolts appear to be torqued correctly.

It appears that there is some oil at the top of the front of the trans where it meets the engine. Additionally, there appears to be some fluid around a switch/solenoid on the D/Side (LHD) of the trans. I'm not sure what this is for but the wiring appears to go up into the floor. It may well be the sport/economy switch.

I would really appreciate any advice as to what this switch/solenoid does as I tried to unscrew it and it broke. Does it screw out and could trans oil come from here in the quantity I experience leaks ?

Any advice as to possible causes of the trans leak would be really useful. Save unecessary costs and all that !

Aussie Andy

1989 500SEL
1989 420SEL
1988 BMW 730i

1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
5,239 Posts
Hi AusssieAndy,

The switch/solenoid I'm pretty sure is the Upshift Delay Solenoid/Switchover Valve (figure Y3/2). Wiring going up into the floor supports that view.

I don't have much on the transmission at all, and I can't see how trans. fluid could get up to the top of the transmission - unless it is thrown there by the spinning torque converter(?)...

Years ago, I had a 3.8 MK2 Jag that spotted the driveway some[:)]. The main transmission leak turned out to be the front seal where the torque converter 'shaft' went into the trans. My 2 cents.

Good luck, MBL


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