1989 300SE Auto Transmission slips - PeachParts Mercedes-Benz Forum

#1 02-03-2003, 09:03 PM

I have recently purchased 1989 300SE 6Cyl auto non-turbo with 130 K miles. It slips when shifting up into next gear (all) on acceleration. Fluid is clear.

I can replace myself ( I think) with a salvaged one, rebuilt, or would like to try some things first.

Also, I assume this is 4 speed with lockup converter. How many RPMS should I turn at about 60. Does ~2800 sound right? Is Dextron the correct fluid.

Any suggestions appreciated.

#2 02-04-2003, 07:50 PM

Also are there any inherent problems to this model Mercedes. This is the first one I have owned.
Thanks

haasman · #3 02-05-2003, 01:55 AM

there was just a bunch of postings regarding this type of problem. Do a search using the word *flaring* I think you will find what you need.

Ken300D · #4 02-05-2003, 08:16 AM

The first thing I'd recommend is a fluid and filter change. If the filter is clogged a bit with use and age, I think that can lower the system's hydraulic pressure. And I have had excellent results with synthetic Dextron-III ATF - currently using Quaker State 4x4 fluid.

I had a problem that started showing up in cold 3-4 shifts. The shift would not execute and the car would just rev. New fluid and filter completely eliminated the problem.

Ken300D
(refers to my 1982 300D)

(also have a 1987 300D)

joe p · #5 02-05-2003, 09:03 AM

bump the modulator pressure and drive it, if the slip is consistent in all shifts, sounds like low apply pressure.

the modulator is on the l/h side of the box in front of the manual valve arm. (shifter) pop the little rubber cap off and turn the enclosed key clockwise 3 turns, put the cap on and drive it..... too firm, back it off in 1/2 turn increments.

if the shifts are late or early, adjust the bowden cable (under the air filter behind the a/f sensor) longer housing, later shifts, shorter housing, earlier shifts.

Joe

#6 02-05-2003, 08:25 PM

Thanks for the advice. I adjusted 3 and seemed like it was still not enough so I went 4 1/2.
This seems to have solved the problem! I hope it holds up. The 1st shift is not as crisp as the others but is very good compaared to what it was.

Do you 4 1/2 was to much and should I consider modular change out, etc.

I also am turning ~2400 rpms at 50. Is this correct because I really can't feel it go into 4th but when I go to 3 it does downshift.

Thanks for all your help.
John L

Snibble · #7 02-05-2003, 11:34 PM

Our trannies start in 2nd gear... maybe thats why you don't feel it going to 4th.

haasman · #8 02-06-2003, 01:24 AM

89nuclear

Have you replaced the trans filter? When you do be sure and drain the torque converter as well.

Haasman

sixto · #9 02-06-2003, 04:31 PM

There's no torque converter lock up.

If the transmission is responding to the modulator adjustments, it's likely not a bad modulator.

Sixto
91 300SE
87 300SDL
83 300SD

stevebfl · #10 02-06-2003, 04:46 PM

If you had to go 4.5 turns something is big time changed. Could be the modulator. I would verify that the vacuum to it follows manifold vacuum (goes to zero at full throttle).