300E shifting hard - PeachParts Mercedes-Benz Forum

mike690003 · #1 10-19-2003, 07:23 PM

Hello Board,

After driving in a friends 300E, I have come to realize that my car shifts too hard. The 2-3 upshift is harsh, especially with the A/C on. My friends 300E has the original tranny and my car has a dealer rebuilt unit. Could it be time to adjust the vacuum modulator?? My car does not leak any fluid and the fluid level is right.

Which direction should I turn the modulator for a smoother shift?

How much should I turn it?

#2 10-19-2003, 07:48 PM

My '91 300E does exactly the same thing and it's done it since the car was brand new. If I have the HVAC on but turn the compressor off, the shifts are acceptable. It I turn the compressor on, the shifts are too hard.

I used to live in Minnesota so it wasn't too much of a problem but now I live in Arizona where we still are having 100 degree days and it's driving me batty.

I'm going to have the dealer fix the da*n thing when I get the transmission serviced.

I'll be interested to see how you resolve the problem.

mike690003 · #3 10-21-2003, 01:44 PM

My car slowly developed this problem (over a one year period). Is it be time for to adjust the vacuum modulator?? My car does not leak any fluid and the fluid level is right on the money.

Which direction should I turn the modulator for a smoother shift?

How much should I turn it?

savas · #4 10-21-2003, 06:40 PM

Here is a great article that will probably answer some of your questions.

http://www.continentalimports.com/ser_ic20242.html

mike690003 · #5 10-30-2003, 12:53 AM

Good article, but I was wondering if anyone knew how to adjust the hard shifting of the transmission via the vacuum modulator.

Does anyone know what direction to turn the little "t" bar adjuster to lessen the harshness of the shift?

The shift points are accurare, but it shifts too hard.

zeronero · #6 10-30-2003, 01:14 AM

Turn it counter clockwise. I had to turn mine nearly 2 full rotations to get it to where I like it.

Freestyler · #7 10-30-2003, 01:16 AM

You turn the little "t-bar" counter-clockwise to get a smoother shift.

Mine also shifted very hard. I adjusted the t-bar as much as two full turns counter-clockwise before it shifted the way i wanted it. -Then it was flaring in the 2-3 upshift, so i turned it ½ turn back again.
Now it shifts firm but not too hard and the flaring is minimized. (it still flares a little bit in the 2-3 shift on full throttle)

Freestyler

mike690003 · #8 10-30-2003, 01:26 AM

Thanks a lot!

I will try one full turn counter-clockwise, and if that does not smoothen the shifting, I will work from there.

Z300e · #9 10-30-2003, 04:46 AM

Where exactly is this adjustment made...I mean, where is this located and what does it look like?? My 2nd to 3rd shift drags out a bit.

Freestyler · #10 10-30-2003, 06:18 AM

Quote:

Originally posted by Z300e
Where exactly is this adjustment made...

Lookie here..

On the picture in that thread you'll see the arrow point to a little black rubber cap. Get under the car. Remove that cap with a set of needle nose pliers. Pull the t-bar slightly out with the pliers and now you can turn it with your fingers. -Not much room up there though..

Freestyler

TX76513 · #11 10-30-2003, 08:16 AM

Do I have an odd ball modulator

It has a large dial like you would find on a timer switch. My movement is only between say 11 o"clock and 3 o'clock

Freestyler · #12 10-30-2003, 08:33 AM

The modulator in the picture is not from a 300E. The 300E modulator is black where this is green. (maybe this is from a 300D? - can't remember what's what), but otherwise they look the same.
(T-bar pulled out and ready to turn in picture)

Freestyler