Hi! I'm a new Mercedes owner, and need a little Mercedes specific advice. My '74 230's automatic slips and slides into 2nd (maybe 3rd?) under moderate throttle opening. If I lift the throttle and dip back in the trans grabs fine. Low and reverse are fine and high gear seems to be fine too. I'd like to take care of this before the trans goes south.

The car has 90k original miles, has only very light surface rust in the trunk, and a great body and interior. I don't want this car to die. It's much too nice!

I'm quite good mechanically so don't be afraid of going over my head with advice. I have quite a lot of tools and have access to many more. I'm a car nut and do just about every repair I can on my vehicles. In fact I'm in the process of building a new engine for my race car, but I have to admit that I know very little about my new MB.

Thank you for the message board, and thank you for any and all assistance!

Joshua Skinner
1974 230.4

Sounds like a modulator valve problem but I'm not really sure if that trans had a modulator valve. I'm old but not that old. If no modulator there a plug where the modulator valve would be and you can remove that plug and adjust the pressures inside there.

I'm that old. The trans has modulator and control pressure adjustments. The easy solution wil be some combination of earlier shift (control pressure linkage) or harder modulator pressure. The modulator adjustment is available after removing the banjo bolt. The 3 or 4 mm allen adjustment can be done through the hollow fitting into the modulator. Turn it a turn at a time clockwise for harder shifts.

I would do a little of both depending on the driving condition.

Steve,

Thank you very much. I will dive into the modulator and see what happens.

Is the control pressure linkage part of the throttle linkage?

I've worked on a number of old Chrysler products that use a mechanical throttle pressure linkage that controls the shift point (throttle pressure versus governor pressure), and the kickdown. They are rather easy to adjust.

I'll play with both adjustments. Hopefully I can get acceptable shifts.

Joshua Skinner

The control pressure is as you describe. The concept, to get it right, is to have your shifts occur before you would naturally let up. If you are letting up the modulator takes a big hit as its pressure varies radically by vacuum. If full load modulator is 60psi, high vacuum might be 15psi.

The reason I bring this up is to help avoid an overly harsh shifting tranny which may be necessary if you overcome this single gear with straight modulator pressure.

PS: relative to the first above paragraph. By letting up, I do not want to infer this to be a full throttle event. I am talking about the activity during your prefered acceleration rate.

[Edited by stevebfl on 07-26-2001 at 07:56 AM]

I've heard many a comlpaint about this problem on these models. A lot of people have just gotten used to driving the car with the tranny slip. I read of a modification done to one of these 230's on line. Check it out at:

www.dhc.net/~pmhack/mercedes/230751.htm

Good luck,

AARON ROCHARD

1976 230.4 W115