Kickdown stuck W124 722.3

[Henkka]

My kickdown gets ”stuck” most of the times I use it (not physically though). I assume the car thinks it’s still being pressed down and won’t let me shift to 4th. Starts from 1st every time the kickdown has been touched while driving. That’s until I pull up to a stop and switch it to P for a quick second and then back to D, then it starts from 2nd again and switches normally up to 4th. Any ideas? This is my last problem with the tranny and when I fix this, it’ll finally after over 6 months work as it’s supposed to.

 

[DREAMER NO2]

Vacuum check on auto box ,,see is vacuum is there for gear changing . Check the small micro switch on the throttle , it should be pressed in with out engine running

 

[Henkka]

Vacuum levels are on point. That microswitch controls the idle, why would that matter? It is pressed in at idle though.

 

[DREAMER NO2]

The switch tells the ecu just what the engine is doing open throttle or stationary and adjusts to suit .Its in the workshop manual to check the micro switch if auto box is having problems operating

 

[alexanderfoti]

I am pretty sure the kickdown switch operates a relay, or a solenoid in the box, Its possible this is sticking on. The kickdown is one of the few things electronically actuated on the older boxes.

 

[mioba]

Deffo the switch on the throttle. You can feel it click before the shifts down and flies.

Had the opposite moons ago on my W124. Flooring it done nothing. Replaced the switch and all was good - 5 min job.

Was about 8 pounds at the time (MB). good luck getting one and keep us posted.

 

[Henkka]

Update: problem isn’t the kickdown, it’s the 1st gear. When I change to 1st manually and take off, the 4th gear is gone.

 

[DREAMER NO2]

You need to read up on this gearbox and make sure you know just what it is suposed to do . So many have posted about a 1st gear missing not knowing that they start in second all the time . How old is the a/box ?, and as it been serviced and filled correctly ? Also check kick down cables are set correctly .There is another item in the car that can cause this ,,, the cruise control ,,have you ever used this and for some reason is still engaged .

 

[Henkka]

You need to read up on this gearbox and make sure you know just what it is suposed to do . So many have posted about a 1st gear missing not knowing that they start in second all the time . How old is the a/box ?, and as it been serviced and filled correctly ? Also check kick down cables are set correctly .There is another item in the car that can cause this ,,, the cruise control ,,have you ever used this and for some reason is still engaged .

No cruise control on mine. 300k km. I know how the gears are supposed to work. Starts on 2nd unless 1st is manually engaged, and when it is, the 4th gear won’t engage.

 

[DREAMER NO2]

That small switch in the throttle tells the ecu its going faster than it is . Or that its not going fast enough and holds it there .

But the main information i found is on this forum ,,and it will help you use the forum search at the top of this page ^^^^ And put in > 722.3 Trans wiring .<
This info is for a W126 but it uses the same gearbox it might or it might not be of use take a look at it first .