I've done it three times now. It's extremely simple. Just make sure everything else is in order to begin with, or you will be disappointed with the results.

Make sure the modulator is correctly set, and the Bowden cable adjustment is correct.

Of course get the requisite couple gallons of ATF and a new pan gasket.

Drain both the pan and the torque converter. Allowing it to drain is what takes the longest amount of time.

 

I just did this over the weekend.

You might consider doing the K2 spring also, depending on how your 3-4 shift is. Mine is a little firm on 3-4.

With my new K1 spring my 2-3 is good, but my 3-4 is a little hard.
We adjusted the modulator to balance them.

Had I known, I would have put in both new springs to balance it better.
Or down the road I will do the other. No big deal.

Also, take your tranny pan and tamp the mating surface nice and flat if necessary. Mine had some dimpling around the bolt holes which might prevent a good seal there.

Draining the TC and the filter change were easy.

 

I just did this over the weekend.

You might consider doing the K2 spring also, depending on how your 3-4 shift is. Mine is a little firm on 3-4.

I'm getting some conflicting results - are K1 and K2 the same part #?
Thanks for all the advices...

 

This is a pretty easy job. My springs were broken into many pieces and my k2 piston blew out the middle somehow. There are pictures of the destruction in a thread of mine around here somewhere. My advice is after you drain the pan and TC, take off the pan and filter and let the valve body drain overnight into a shallow rubbermaid or something. Else, you will have stinky sticky ATF fluid all over you. Also, be very clean with the whole process after you have removed the tranny pan; lint free towels, spotless prep areas and such. Small solid contaminants will hose your valve body. Hell, if you follow the maintenance manual to the letter, they say to use a leather cloth for wiping the tranny dipstick.

 

Got this from Hattenator thread...:

Just an added note for further information to those that read this post the K1 kit will replace the parts for the K-1 and K-2 if you look at the ATSG guide on the modulator DIY that I posted you will see how the valve bodies of these transmissions breakdown and where the K-2 is located. It is a twin to the K-1 but does a different job but not a bad idea to replace both while you already have it appart.

http://www.benzworld.org/forums/w201-190-class/1361737-diy-mercedes-722-3-722-4-a-2.html

 

Did the K1 last week and fixed my flare from 2-3.
But now my 3-4 shift is firmer than my 2-3.

And since we have a small leak at the pan, I am going to get another K1 kit (126 270 44 77) and see about that K2 spring while the pan is down.

Will advise later today.
Tj

 

Im still waiting for my part to arrive...gonna do both at the same time.

 

Due to a small leak I pulled my tranny pan again.

Armed with a new K1 Spring Kit (126-270-44-77) I pulled the cover for the K2 spring that controls the 3-4 shift (Mine is a touch stiff compared to 2-3).

It looks like the K2 internals are different from the K1 internals so I aborted that mission and put it all back together.

K2 cover is on the lower left of the valve body in this pic.

K1 spring kit sitting next to my actual K2 spring.

Putting it all back together.

 

Due to a small leak I pulled my tranny pan again.

Armed with a new K1 Spring Kit (126-270-44-77) I pulled the cover for the K2 spring that controls the 3-4 shift (Mine is a touch stiff compared to 2-3).

It looks like the K2 internals are different from the K1 internals so I aborted that mission and put it all back together.

K2 cover is on the lower left of the valve body in this pic.
View attachment 339650

K1 spring kit sitting next to my actual K2 spring.
View attachment 339651

Putting it all back together.

I have my K1 kit just arrived but then i ask my parts guy to go ahead to order another set (126-270-44-77) to replace my K2 spring. If the K2 is different, anyone know what is the actual part number for it? My ride is a 300SEL.

 

I bought a spare K1 kit from Mercedes of Avondale (Phoenix).
If anybody needs one it is surplus to my needs.

Tj

 

do you still have the kit

126 270 44 77

I need to do this service on my 95 e320. Flare at 2-3

 

They have an MB dealer in Avondale now?

(I'm thinking out by I-10 and 99th Ave?)

Never mind, if you're looking to see that the K1 kit goes to a good home, I'm sure that either the 300TD or 380SL will flare 2-3 eventually. Heaven knows the 300SD and 420SEL did!

 

Bell and like 986th Ave. WAY out there.
Actually right near 101 and Bell. (92nd ave)

I bought this second K1 kit because I thought it would work for my K2.

You are welcome to it.
I think it cost me $17 bucks.

Tj

 

After removing and replacing my K2 spring in my 722.3 1988 560SEC my 3-4 shift now drops like a ROCK.

I can't imagine how I got the accumulator and springs back in wrong but maybe I did.

Does anybody have any pictures of the K2 setup?
This is where I left off...

 

I am kind of waiting for someone to speak on the K-2 topic as well since I am going to do both also. Quite soon actually.

Is that a green TR7 (8?) in the background in the pic you posted of the valve body?

-Wolf

 

That is my green 240z project. Still in process...

I will have to go back in and see what my K2 looks like again.

I really didn't understand how that assembly went together.
There was a spring and a flat thing inside the accumulator plastic body that didn't want to come out. So I didn't force it.

The pictures in the tranny manual just aren't very clear.

tJ

 

Word on the street is that a K2 failure is so rare you will never find anyone talking about it. The items discussed on here are known issues as people discuss them as they happen. I spent a very long time researching the k2 springs here and everywhere and found evidence of only 2 failures which may have been the same guy on different forums. Bottom line is that finding the part number has even proved hard for the dealer here. I must admit that let some old guy out of a closet every time I come in for a w126 question cuz everyone else just says "w126, w126, w126, you said transmission right? w126, KY what? Do you have a part number?"

 

My k2 seemed a lot different from my K1.

Note in my picture there is a spring and a plastic thing that was "stuck" in the piston body. I pulled a little and twisted a little but it didn't want to come out without more force.

So I quit, put it all back in as best I thought it came out and now I have a pretty harsh 3-4 shift. More than before.

Honestly at the end I couldn't remember if the big and little spring go in the same hole with that other captive spring, or if it was supposed to be the other way around.


Superior Shift people are faxing me some documents on the K2 now.

 

Superior document by fax for K722a-G Gas models.

View attachment Superior K722A-G.pdf

 

Yeah I looked at their stuff but the group was so small and looked like they were all on the same forum which made me believe it was a marketing thread. Besides its not MB

 

According to that I think I have a 2 spring train.

 

That would be the same for the K1 I believe as well. Its an inline bunch of parts/springs. I have not been able to see much difference in them when I pulled everything apart. I left the K2 as it was intact. It did appear to touch shorter than the new K1 but it has had some time to compress. I think I read your shifts are harsh and I can only imagine that would get harsher if a new spring was added. Modulator pressure would be my first area to look here. Good luck

 

I don't know how much help this will be but here is the link to my piston repair saga. Unfortunately, I ultimately decided to replace the tranny.

http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1505331-menu-starting-now.html

Anyway, I agree with a previous poster that harsh shifts can be adjusted with the modulator. Have you checked the pressure and adjusted it according to your transmission model? Harbor Freight sells an oil pressure test kit for only $20 bucks with the right fittings to check the oil pressure at the modulator. Then, you just adjust the modulator while looking at the gauge until the pressure is correct. That gives you a baseline to start with. You should also check your vacuum back to the engine. Mine was 18hg which is within spec.

 

Foolio:
I am looking at this picture of your K2 setup.
Are you 100% CERTAIN that is the correct orientation of the parts as you removed them?

I installed my green valve body the opposite direction that it is depicted from yours.
On the right side of your picture you can kinda see the little inner spring pointing right.
But all the other springs to the left.

TJ

 

I am pretty sure I put my K2 together wrong.

That little spring that is captured inside the piston went facing INTO the valve body on mine.

But judging from this document (See item #49) I think I screwed that up and put it in backwards.

View attachment tranny_722_repair.pdf

I will re-do that today.

 

Pulled the pan, ATF and filter and opened the K2 cover.
I reversed my previous installation of the K2 piston.

On MY K2 piston it is open on both ends with a barrier in the middle.
There is a small spring and plastic cover on one side and the other is open (see previous pics.).

I previously incorrectly installed ALL the springs towards the inside of the valve body.
So I had the little spring inside and the "2 spring train" inside too.
This resulted in a hard drop of 4th gear that wasn't there before.

This time per the drawings I installed the piston with the little spring facing aft as it was originally and the 2 spring train on the other side towards the VB.

Now my 3-4 shift is back to where it was.
Crisp, but not dropping hard.

Best part is that it doesn't leak.
Torquing those pan bolts per the book spec is key.

Tj

 

Hey, glad you got it figured out. That picture was to merely show the destruction of my piston and spring. The middle was gone and one of the ends was all chewed up. Plus, the big spring was in half a dozen pieces. Sorry for the confusion.

 

Your picture was very helpful and based on the MBZ pictures it straightened my situation out.

However, I spent a half-hour on the phone with the tech support guy from Superior Transmission. He said he has worked on these Benz trannies forever.

He said to strip that piston clean - take everything out - just install their 1 spring and call it a day. Down the road I will probably do a pre-emtive B1 piston and install the Superior kit in K1 and K2.

Great learing excersize.

 

Hi Guys

I just love this forum...managed to fix my trans shift point after adjusting the Bowden Cable tighter (Clockwise). I always have the feeling that my trans (after rebuilt) starts in 1st every time plus drags on till 3000rpm before upshift to 2nd. Now from standing start it will smoothly glide away in 2nd and the engine doesn't sound so loud anymore at 100-120 km/h. Throttle response is amazing with a slight feathering the engine felt eager to move without hesitation.

Anyway i have my K1 kit waiting to go in...plan of doing it when i change the trans oil this weekend. Still fine tuning the bowden cable....