Hello

I have a 1992 500sel with 168k miles. The car is in mint condition, the engine sounds and runs like new. But the tranny shifts harshly into third or fourth gear every time. it sounds like a big thud. The tranny doesnt slip at all and it shifts flawlessly into other gears. What do you guys think, please let me know.

 

does it have "B" switch on shift gate?
with the engine running, there must only be voltage (10-12) at the kick-down solenoid valve when the selector lever is at "B" and/or kick-down is actuated.

go down there and check. the kick down solenoid is on the rear end of the transmission, black color with one black wire attached to it. check the voltage of that wire. if voltage is always present, open the Bswitch (remove the shift lever cover, just pull it up) and replace it.

if you have no b-switch, then it's the teflon rings of suppport flange K2. replace clutch K2 if possible.

 

Do you think the problem is electrical or mechanical. so you say i should put it in B while its on a jack, and check the voltage at the kickdown solenoid valve. if you could elaborate and make it more simple at the same time i would appreciate it. Thanks

 

exactly.


ignition on

0 shift to p, r, n, or d

1 jack up the car

2 ignition or start the engine (if your jack is 101% secured)

3 go under the car on the rear end of transmission

4 look up and see the wire

5 if you see the wire, go and get a voltmeter, or multi tester, or test light

6 pull out the wire from the kick down solenoid

7 check if there is voltage or current on it.

* have voltage = faulty B switch

*no voltage = check the kickdown solenoid. you will find a small piece of rubber blocking the hole! remove it. apply 12 volts to it. you must hear and feel it "clicking" and see the plunger inside moving.

step 2:

have someone inside the car and push the accelerator pedal all the way to the floor till the kickdown switch is acruated (he can feel the thud).

repeat steps 0 to 7

have voltage = good kickdown switch
no voltage = bad kickdown switch

step 3:

shift to "B"

repeat steps 1 - 7

have voltage = good B switch
no voltage = bad B switch

step 4:

get a cup of coffee and figure it out.