Failing vacuum modulator???
 

Interesting.

Finally decided we could fit all the gear and suitcase into the 560 for the trip to Sacramento. Then decided to make a run to the bank for some travling cash. Halfway to the bank, coming off a stop light I get a 1st gear start on easy throttle. Then it decides to hang in first gear. A couple throttle blips wont force an upshift.

Coming off the next stop light I did so somewhat aggressively. That forced an upshift to 2nd. The car has been shifting fine since. The only thing I can think is that the vacuum modulator might be failing, early stages. What do y'all think?

BTW, since that little first gear lock up, I have decided to take the Suburban. Really don't want to get hung in first all the way through the Central Valley.

Could be that the carpet is caught up in the kickdown switch or the switch is sticking.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Mike

Bummer! It sounds like a vacuum modulator or possibly the rubber tubing between the modulator and the vacuum line.

Hope you had a good trip never the less.

Haasman

Mike,

How is it and what was it?

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Mike, if your car has the manual select switch for first gear it could be sticking. If I remember correctly, all 5.6L MB's had this feature. With the shifter in 2nd gear, a click to the left engages first. Sometimes the switch doesn't release and causes some strange transmission behavior. Good luck

Just got back late last night, haven't had a chance to check anything out yet though.

Yes, the 560 has the "B" switch for 1st gear lock, but I have only locked it a couple times. The most recent manual 1st gear lock was probably a couple weeks ago. Will keep that in mind if it happens again.

Don't think it could be the kickdown switch because of the circumstances when the event happened. I was rolling at speed, slowed to a stop. Light went green and I gently accelerated and made a right turn. That gentle accel caused a 1st gear start.

Will also have to check out if I may have had a minor coffee spill right into the "B" switch. Possible a liquid short could have caused this.