1993 M104 Kickdown Failure
 

I have a 1993 300E with M104 and 722.4 transmission... one day... i noticed my kick-down wasn't working... so I bought a new kickdown switch. It DID NOT solve the problem.
The gas pedal is broken and could be replaced... I'm thinking that the variance of not properly aligning (still hits the kickdown switch though) might not be telling the ECU that it's at WOT??? So if gas pedal gets replaced... and still nothing.... where do go from there?

It sucks when going about 8 mph and really need to get up and move... and floor it and just get no power!! Even dumping the gearbox won't get u into 1st gear unless stopped or going slow enough with enough engine load....

Thanks for any insight.

Have you checked and adjusted the control pressure cable?

there is a kickdown solenoid on the transmission too, make sure its not bad, and firstly make sure that the transmission is adjusted correctly which entails.

1 transmission fluid level correct (for dead cold 722.4, the level should be at the curl of the dipstick - not at the scale)

2 - pressure cable correctly set (zero pressure at idle)

3 - vacuum modulator correctly set. (incorrect causes slipping or super hard kick)

I did recently add almost a quart of tranny fluid...

I'll check the fluid level. so when u say "cold" that means that I just start the car, let it idle for about a minute, and then test the fluid level?

Control Pressure Cable...
 

Sorry, missed that post... Control Pressure Cable? Nope.. I know nothing of it. where is it and how do I test it?? Thanks!!

yes - exactly, and if you fill it till the 30 C line you are about nearly 3/4 a quart overfilled,

the correct level at that temperature is where the dipstick curls up into a pointer.

I think I'll take it to my independent mechanic and have him drain a good half quart after I check the fluid. Thanks!

just a quick Q...
 

Haven't had my mechanic drain a little fluid yet (might be time for a str8-up fluid and filter change.... hmmmm...)...

but I'm curious, how exactly does that extra fluid directly affect Kick-down from working? THanks! Curiousity .... ;)

David, as you're probably aware transmission fluid and filter should be changed every 30,000 miles in that vintage MB automobile. Proper fluid level is checked with the engine/transmission at operating temperature and the engine running with transmission in Park. So leave a pint, or so, out until you drive the car and get it to operating temperature. Then add a few ounces at a time until achieving the proper level on the transmission dipstick.

That is a great idea. If someone were to ask me, I would have said 'normal operating temp' too. I just took a cougher of some chronic, and now I feel really GOOD and goofy.. Ahh yes, back to that tranny fluid (eww!?), I'll check it this weekend and probably have it changed by my Benz guy next week.. I always order my own parts from..... right here! Not always the least expensive, but the customer service more than makes up for it, Have a great weekend.

PS: I have driven this car for maybe 18k miles in the past 8 months since I got it. I could be way off as the car's adomoter is stuck in 214,190 or so. I'm sure it's due anyway. and it's some of the BEST PREVENTATIVE MAINTENANCE EVER!

The control pressure cable runs from the throttle linkage near the intake manifold to the transmission. It needs to be adjusted to zero slack at idle.

Okay... i know of the cable.... and i suppose it's one of those "screws" on the cable (at the linkage of the Throttle body or?) that I twist ...

Yes. Going from memory, I don't recall any tricks to it.