109 transmission will not hold in park

[tosbt]

This is a 4.5 and I took it to a tech and had all the gaskets and seals replaced. It will not start in park unless I push it all the way forward and at times WILL ROLL BACKWARDS. Shifts out perfectely. I am taking it to a new mechanic in the morning what should I ask him to look for? There must be some securing pin that is not engaged or adjusted properly. Any Ideas?

[Tomguy]

Mine has done the same thing since the tranny was "Rebuilt" by a local shop that didn't know what the hell they were doing AGES ago.

I think the pin that holds it in is either bent or maladjusted. I just properly adjusted my parking brake so it will hold my car on a hill, and don't worry too much about the tranny holding it.

[tosbt]

Tomguy, something must make it hold in place. I think it must be an adjustment something simple.

[H-townbenzoboy]

Could be the shifter bushings. That's what my W123 would do, until I had the bushings replaced.
-Joe

[MikeTangas]

Column shift?

If so the shift tube bushings in the steering column are shot...something like a $5 part. My 4.5 does the same thing in that I have to lift it all the way into park in order to start. Also, the parking pawls on the older transmissions aren't as beefy as those on a W126. Might also want to check the condition of the shift linkage bushings.

[tosbt]

Thank you my friends!

Originally Posted by MikeTangas

Column shift?

If so the shift tube bushings in the steering column are shot...something like a $5 part. My 4.5 does the same thing in that I have to lift it all the way into park in order to start. Also, the parking pawls on the older transmissions aren't as beefy as those on a W126. Might also want to check the condition of the shift linkage bushings.

I learned the hard way parking pawls are weak on some of the older transmissions. I always use the parking brake now. I think parking pawl can be replaced with trans in car. You could, at your own risk, by pass the neutral safety switch as a temporary measure. The switch might be able to be adjusted to compensate for wear in the shift linkage. btw how's that air suspension doing? I used to have a 3.5 W109 and have walked out on many a cold morning to see the car looking like a low rider. That air ride is hard to describe. Real old world luxury and precise handling. Enjoy

[tosbt]

I completely replaced my air suspension two years back and it does very well. Never low and the ride is truly amazing for a 33 year old car. Bit by bit I'm trying to bring this car up to a very high standard really having a hard time finding a tech that can and wants to work on this car. Sometime I just want to ship it off to a guy like Psfred and say "call me when you are happy with it". I found a new guy this past week and I think he may be the one to sitck with this car. Thanks for the advice.

[cth350]

it's either the pawl or an adjustment problem. Start with testing the transmisison w/o the linkage attached. Put the rear up on jack stands, undo the linkage and work the transmission through the gears. All the shift points are close together except park. Once you put it there by hand w/o the linkage arm attached, the drive shaft should lock in place. If it doesn't you need to replace the pawl.

-CTH

Originally Posted by tosbt

I completely replaced my air suspension two years back and it does very well. Never low and the ride is truly amazing for a 33 year old car. Bit by bit I'm trying to bring this car up to a very high standard really having a hard time finding a tech that can and wants to work on this car. Sometime I just want to ship it off to a guy like Psfred and say "call me when you are happy with it". I found a new guy this past week and I think he may be the one to sitck with this car. Thanks for the advice.

The trick is to completely replace the air supspension at one time. I have found the valves to be the cause of most leaks. Neil over at STAR MOTORS is great to deal with. Most of the old Mercedes techs with w109 expertise really treat these cars well. They really care about preserving the car. Having a good tech really makes or breaks w109 ownership. Good luck.