Shop Manual K4A025 Transmission?

[TheEngineer]

I have been looking for a shop manual for my automatic transmission: I have an early 1969 280SL with the K4A025 automatic. The only workshop manual I have found is entitled: " Automatic Transmission with two Planetary Gear Sets" Assembly, Service & repair, Passenger car models 190C through 300SEL (from Workshop manual, passenger cars as of 1959"  There is no publication number that I can find, but on the first page there is an index: Automatic DB Transmission - Group 27 and on the bottom it says: "25-Supplement Nov 63 - Workshop manual Passenger Car 1959".
Looking thru the manual it appears to describe the transmission in my car. I'm puzzled by a listing on page 27-0/4b which shows the manual to be applicable to W113 230SL with a transmission type GA 230 SL-E.
I have the GA 280 SE transmission.
What is the difference between the GA 280 SE and GA 230 SL-E ?
Thanks !

[68_white]

Greetings to my fellow engineer.

My transmission has the same stamp type "280SE" and it is coorect for my car,since the serial number matches the one in the data card. From what I heard, MB made these transmissions for several models, and thus the different tags "230SL", "280SE".  It did not matter to MB what the tag said when they were installing them.  They are the same K4A025.  I have another manual that is a copy of a copy, which I bought from "dfaterone" on ebay. I can give you a description when I find it.

HARRY

68_WHITE

[68_white]

It looks that my manual is the same as yours. From what I can see, several of the pages have been updated at different dates up to 1966? So, it would not cover our cars.  One thing that I saw at my mechanics shop, is several K4A025 transmissions with different tags such as 230 SL taken out of a 280SE. It does not make sense to me but as long as it is correct and works properly I would not worry about it.

HARRY

68_WHITE

[TheEngineer]

68 White: Thank you very much for the comeback. I spent some time yesterday studying that manual and comparing it to the text in my BBB, which is for the 280SL. It appears indeed that the transmission manual is applicable. It's so much easier to read at home rather than in the bookstore where I'm under pressure to make a quick decision to buy this or the other one. I also checked the s/n of my transmission against the dada card and it matches. So, thank you for your help. I'm curious: How smooth does your transmission shift from 2 to 3? Mine shifts very smooth all the time when it's cold, but after I have driven for about 20 miles, it sometimes shifts harsh. It is not consistent. Most of the time it shifts so that I don't even notice. But then, sometimes, only when I have driven quite a while, it gets my attention because it just shifted up with a pronounced jolt. I did drive another Pagoda for enough time to get it hot and it shifted very smooth all the time. My transmission is probably mis-adjusted. Any comments?

[68_white]

Boy, oh boy, do I have transmission stories to tell. I had my transmission overhauled about a year ago. After many adjustments my mechanic got it working. Yes, I have similar problems. When cold shifting seems smooth, but when warm, shifting is a little harsh. Most annoying is shifting down when I come to a stop, from 3rd to 2nd. I really feel it. I am still working with my mechanic trying to get it adjusted properly.  But first we must finish the piston replacement job.  Check out my other thread.  I got stories to tell about that job too.  I will let you know what I find out, hopefully soon.

HARRY

68_WHITE

[ja17]

Hello Harry,
If your transmission downshift from 3 to 2 is harsh, you must check the venturi to make sure it closes all the way, then adjust the venturi switch.  This is usually the cause of harsh downshifts. Search up the procedure. There are lot of posts on it.

Check back if you  are not sure how to do this.

Yes the GA 230SL-E and the GA 280SE Are basically the same transmission type K4A025. The  internal working pressures of the two are set slightly different.

Joe Alexander
Blacklick, Ohio

[TheEngineer]

Thanks Guys! All my down shifts are not noticable at all unless I really pay close attention: I noticed it appears to downshift at about 1,000 RPM, regardless of which gear. So, when I'm in 4th and my RPM drop below 1,000, it shifts into 3rd. Likewise, when I come to a stop, it shifts down from 4th to 3rd to 2nd. But it is barely noticable and without looking at the tach, and expecting it, you wouldn't notice. I'm studying this manual and it is exhausting reading. Like a college course. But I believe, the transmission can be made to shift very smooth and rough shifting is because of wear or misadjustment. Interestingly, when MB first delivered cars with that transmission, the reviews were excellent. When the cars became older, the reviews started to complain about rough shifting and today, it is published that you must expect it. I also noticed that the K4C025 transmission, which was installed in cars after May '69, but not in the Pagodas, starts out in 1st gear.

[ja17]

Hello,
Yes the K4C025 is a completely different animal. It is a smoother transmission. It has a different physical size, opposite shift pattern, and different electrical hook ups. It also has an accelerator linkage rod regulating shift points.


In general Mercedes W113 automatics (K4A 025)of the era were a bit firm shifting compared to the American cars. The reason for this is  the clutch pack stops completely before engaging in the Mercedes unit (you feel the change) so clutch wear is virtually non existent. Other automatic transmissions allow some slippage to give a smoother shift but the clutches wear.

Generally the W113 transmission shifts are pronounced but should not be harsh. You can achieve smoother than normal shifting but be careful not to introduce clutch slippage.

Joe Alexander
Blacklick, Ohio