Page 2

A closeup view of the cover that the spring kit fits inside.

Take out all but one of the screws and leave the cover hanging from the loosened screw (see Pic). leaving the piece there gives less risk any dirt getting on the cover while working. Under the cover you can see the little green piston holder. The internal spring has pushed it out a little here – making it very convenient to grab a hold of and slide out. There is sufficient clearance to remove and replace the green holder without any risk of damaging the two O-rings on it.

A closeup of the piston holder.

Here's what came out. The green piston holder and the internal spring mechanism. The parts inside the green holder is what we'll be replacing with the K1 spring kit.

Here's a picture of what is inside and how it was ordered. The small coil spring goes into the holder first, then the plastic-with-dual-spring valve.

The new spring kit pieces side by side with the old spring kit pieces. The large and medium spring go on the white post, the white post is (carefully and straightly!) inserted into the black piece until the assembly clicks and stays together on it's own. It takes some force, and if not done delicately and inserted at an angle, others have found out that the black piece can be cracked where the white piece is inserted.

You can't see it in this picture, but the long spring is beefier and the short spring should be weaker since it is of the same gauge but has one fewer coil. The medium spring is about the same between both assemblies.

Here's the assembled new spring kit (bottom) ready to be replaced alongside the old one (top). Here, it can be clearly seen that the new long spring is beefier and the new short spring has one fewer coils.





Installation is the reverse of removal. Briefly, put the little spring in the green holder, put the black end into the holder and make sure it fits inside the short spring. Take the assembled part and reinsert it back into the hole from where it came. Push it in, slide the cover back over it, then put the screws back in and retighten them to about what they were before. I've found no torque specification on how tight to make the screws, so I just did it by feel trying to match the previous torque. However, a word of caution – the valve body is aluminum, so it wouldn't be too hard to cross thread or over-torque the screws and strip the holes. You'd have a really bad day if you did that, so take it easy.

I did the transmission filter last. It is held in place with three phillips screws. The offset screwdriver came in handy again here for loosening the screws as they were in there pretty tight.

Clean the pan, gasket and the part of the transmission where the gasket contacts it, reassemble and torque all the bolts to specification, then add the ATF as per MBZ's procedure and off you go.


For other transmission shifting probelms you can also checkout this pagehttp://www.benzworld.org/forums/w201-190e-d-class/1360821-diy-w201-transmission-modulator-removal-replace-trobleshooting-common-problems.html

 

Hello HATTENATOR,
You seem to know a bit about transmissions; I hope you do not mind me consulting with you in regards to the above mentioned. I have a 1991 190E 2.6L and just ran into the AT modulator valve change ordeal. I do not know if I might have ran the car a little too long with a low ATF level. I ran the car approximately 8 miles with a white smoke cloud behind me before I was able to stop.
Any how, The AT mod valve now changed, I am experiencing delay shifting from 2nd to 3rd gear. When driving normal it is barely noticeable but when I give it a little gas it lingers (slips) for about a second before shifting hard. I still have not tried floring it as I am afraid I only make it worse. I should mention that when finish replacing the AT mod valve I refilled with only 2qts of ATF back to normal level. Not sure about capacity but I am sure it holds more than 2 qts so it was not completely dry.
Do you thinks the problem will go away by doing the K1 kit change or this is actually something that happened and there could be more severe problems in with the transmission due to running it nearly dry?
Rgds,
Erick

 

the way you discirbe the promlem sounds just like the K1 spring problem alot of owners have. For the 10 bucks it costs for the kit and some fluid and filter I would go ahead and install the kit.

When you drove it smoking did it slip any at all.

Did it ever do this before the modulator problem

and are you sure you have no vac leaks and the modulator is adjusted correctly.

It is possible that something else could have been damaged if your tranny started slipping when you had the problem but I think it is the K1 springs.

There is also an aftermarket kit out there I never listed. It will help with alot of different shift problems on the 722.3 and 722.4 transmissions but it is more expensive but it can do alot more. This in adition to the original one being replaced first

 

Hello Hattenator,

Thanks for your quick reply. Before the incident it was not slipping nor did it slip during the smoking. During the smoking I did notice it shifting hard thoug and car felt as if pulling a boat (could have been loss of power due to excess ATF burning). I know for sure the ATF pretty much burned the spark plugs as I had to change them and they were burned like nothing I ever saw before(don't know how the engine even started). Today however, I noticed for the first time another symptom. When the car is placed on park and then back in drive, the transmission does not completely engage in 1st. It engages 1st on the first bit of gas I give it-did it while car was cold and hot. Never did that before, not even yesterday. It only does it when in P and then to D it does not do it when I come to a complete stop.
The mod valve was only changed. I had the red cap one and replaced by another red cap but no adjustments were made; also have not tested for vac leaks. Will go for the K1 kit, ATF and filter and revert.
Krgds,
Erick

 

After you change the K-1 kit I would check the modulator pressure and make sure it is set correctly since you have not adjusted your modulator. You can get the correct settings for your transmission here. http://www.benzworld.org/forums/w201-190e-d-class/1360821-diy-w201-transmission-modulator-removal-replace-trobleshooting-common-problems.html This is a must do after a modulator change the modulator should be set corretly and not just randomly.

 

I am having the same flare problem with my 94 500SL. I read through your article and I am pretty sure it is the same issue; my SL has a 722.5 transmission. However, I am having trouble finding this kit. Can you offer any suggestions?

Thanks!
Phil Vorwerk

 

Phil

You should be able to order this kit using the part number on the package from your local Mercedes dealer. I have not found anyone but Fastlane, online that has this listed but I know it can be purchased directly from the dealer. If you have any problems let me know

I have also added this link for mercedes shop fastlane they have it but I think you can get it from MB cheaper MercedesShop FastLane

 

Wierd, wonder why this didnt make its way to FAQ, oh well added now. Great help hattenator

 

Thanks, I was able to get the part from Mercedes Shop. The mechanic who was trying to order this first told me it was a bad part number, then told me that it was backordered. Perhaps he copied down the part number incorrectly.....

By the way, thank you for posting such a well illustrated, detailed DIY procedure for this. I would tackle this myself if I had a rack; I'm just not into laying on my garage floor underneath my car anymore.

Thanks!
Phil

 

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.

 

Greetings, this is my first posting to this forum, but I have been reading it with great enjoyment. Bought an extremely clean 87 420SEL a few months back and have been dialing it in with your help. I tackled the K1 spring refit yesterday and it remedied the 2nd-to-third gear flare. I bought a second kit from the dealer to take care of the K2 spring while I was in there, but I was surprised to find that the K2 accumulator valve was completely different from the K1 on my 87. It had springs on both sides of the green plastic valve body and the springs were shorter and narrower than the K1 springs. Basically, nothing in the K1 kit was interchangeable with the K2 components, so I just put the old K2 assembly back in and sewed her up. So, although the 2-3 flare is gone (sweet), I do have a touch of it in the 3-4 transition and would be grateful for any advice for the next time I have the tranny pan off. Anyone else encountered this? Is there a spring replacement kit for these oddball K2 assemblies? Much thanks for the tribal knowledge; it has been invaluable.

 

I was going to ask if the same kit worked for controlling the 1-2 shift and the 2-3 shift. I was just thinking that I should have replaced both right away. It did clean up the 2-3 shift nicely; the shift is very firm and crisp. I am now noticing that the 1-2 shift will flare slightly every once in a while, but not nearly as bad as the 2-3 shift had been. Thanks for the info.

Phil

 

HATTENATOR

Hi to you all, I,m from the UK.
Hattenator thank you for all the hard work you do on this forum.
Very good reading bud.
Can you help me please, I have just purchased off ebay a 1999 Daewoo Musso with the Mercedes 2.3 16v petrol engine with 109k miles.

The gearbox is a Mercedes four speed auto, the box is a 722.378.
The problem is no second gear, it goes into drive OK, sets off OK then you have to take it to 4k revs. then she goes into 3rd OK and then smoothly into fourth gear.

I drained the gearbox fluid into a 10 litre bucket and its nearly full, I haven't drained the torque converter yet!!!!!!!!!!
I have removed the valve body and stripped and cleaned it. all the plungers and springs seem OK.

This afternoon I removed the Modulator Valve and plunger, I connected it to some vacuum pipe and sucked the pipe, the plunger in the middle of the modulator went in, as it should. I then clamped the pipe for 5 Min's and the plunger stayed in. I then removed the pipe and pressed the plunger in and gearbox fluid squirted out of the small plastic pipe were the vac pipe connects.

Any help would be really appreciated :bowdown:

StayLucky
Jim

 

I also attached a copy of the ATSG guide for this tranny tohelp you better understand what the parts are where they are located ATSG 722-3 & 722-4.pdf

 

Hi Hattenator,

Thank you for the reply, much appreciated. I have stripped and cleaned the valve body. Fitted new filter and new ATF, Still the same no second gear :crybaby2:


Time for a deeper look...
Take care
Jim

 

2nd gear is controled by the b1 piston and b1 brake band you can reference all of these items in the ATSG manual. This may be a problem you can fix on your own by following the troubleshooting guide depending on your level of mechanical ability or it may require the assistance of a professional. I have messed with several of these trannys and they are usually pretty easy to work on and repair once you understand how they work and what each part does. keep us up to date on what you find out conclusions to a problem often help many later down the road.

This is another insert that may help you to understand how the tranny works and what parts the previous post was describing http://transtec.com/tech_insert/94642.pdf

 

THANK YOU! For your help Hattenator
I will keep you up to date with the progress and photo's of any damaged parts. When you remove the B1 cover, I see it shows a special tool to use. How much tension is on the cover when you remove the snap ring.
Thanks again :bowdown:
StayLucky
Jim

 

Halo

Here's a report on how's it going after 6 months or better that I installed the 2-3 Flare Spring Kit as reported at the time on Hattenator's other full thread.

I had at one time the dreaded really hard 1-2 shift especially when cold ( calif cold ) This was resolved after doing a Head Gasket replacement where I believe a Vacumn issue was resolved and two, new Motor Mounts which WoW'd me on how much better shifting and idle vibrations were tamed.

Then the 2-3 Flare issue which was intermittent depending on Throttle/RPM. Under say 3K and 1/4 throttle it wasn't all that bad or not at all. Over 3K shifts and usually fully warmed up and especially hot days 2-3 Flare could go as high as a 500 RPM's and a lazy engagement. 1/2 Throttle and up best guess would be 300 RPM's and a bad one would be up to 500.

After the Spring Kit, Filter,Gasket and Fluid change: Shifting 2-3 was much different. Normal traffic driving 1/4 Throttle or so and any shifts below 3K are about a perfect as one could ask. Above 1/4 Throttle and say 3K and up, the shifts are very acceptable as a Norm. IF a Flare does show up, it still can, the difference is max flare might goes as high as 200 RPM and she goes in much quicker. It's not a Hard shift like a bang, but can be rather firm at times.

What is surprising to me, mechanical issues IMHO just don't away on their own. The might Hold their own but over time they just get worse to the point of failure and now you have to do something. After a number of months my 2-3 shift has actually improved even more and quite nice. On occasion ,again depending on Throttle/rpms and Heat, a flare can show up but she gets over it rather quickly and not quite as Firm as in the beginning.

Did the springs soften up a bit? Did the Bands sort of reseat themselves over time since slipping was basically gone now? I don't know. All I can say is life is good. I have a new Modulator purchased months ago and it still is in a box. Just has not been an issue I need to go after. I do need to get around to it just to see.

Bottom line is, go for it. With the pics and instructions on the other full thread it is quite easy to do. Auto Transmissions can be a bit intimidating, just examine the pics and make sure you are in the correct location, lots of screws and cover plates. You can do it and I highly recommend it if you have the Flare.

regards
Dan

 

where is it possible to buy this kit please.
my car have this problem :crybaby2:

 

The part number is in Hattenators write up. I got mine at the dealer and it was actually cheap.

I did see at the time other places that sold a spring kit for all the shifts. No clue where though , sorry.

Dan

 

I bought the K1 spring kit at Ray Catena of Union/NJ for $7.

 

Logon Bob thanks for for posting the followup on how yours improved I have been gone for a while and I am glad to see yours got better

 

Hey,,, there you are.

You're welcome. Some thing else, when ( though rare these days ) a mild flare does show up and usually only when it get hot out doors, backing off the throttle just a bit at the right time about eliminates and flare at all.

It's a bit tricky with timing and just a little too much backing off the throttle will just go right through to 3 rd gear. This leads me to think I need to get around to putting in the new Modulator I have had for ever.

To compound the issue, running the A/c or say going up a hill where you are now applying more throttle but less related speed ( aka a drop in vacuum ) the flare can show up more readily and again I am hoping it's the modulator needing a slight adjustment, or a new one.

Really, it has not been all that bad so I have not been pressured into to changing it out. Most times it is quite delightful. One day...

Dan

 

glad it woking but it sounds to me like you are just procrastinating at the wonderful and glorious task of changing and adjusting the modulator. I am sure that task is not at the top of anyones favorite things to do list.

 

You got it..

Dan

 

Would this apply to my 1994 c280 transmission too? This is my problem!!

 

the 1994 to 1996 C280 has a 722.424 transmission it is in the 722.4 family of mercedes transmissions so yes it should work for u. here mercedes722.pdf is a pdf on your transmission that gives you the breakdown of the valve body and it shows the k-1 you might want to make sure the replacement parts are the same for your year but the function of the tranny is the same and I would think the parts would interchange.

 

Great thanks bud, ordering now!

 

my 3-4 shift feels kinda soft when I have driven the car alot. What kit would firm up that 3-4 shift?

 

wow guys, this is a great thread.

i had my modulator replaced about 6 months ago because the diaphragm had ruptured and I was getting a lot of white smoke. I'm not sure if the mechanic made the proper pressure adjustments or not (probably not). After the modulator was replaced the transmission shifted better than it had in years through the entire sequence 1-2-3-4.

However, the transmission now flares significantly when shifting from 3rd to 4th. Its not a major issue when I can ease off the accelerator to induce the shift in normal travel but if I need to accelerate quickly the flare between 3-4 is very bad as the rpms will spike as much as 1-2kfor approximately 1-2 seconds.

I have seen a lot of great help for shift issues from 2nd to 3rd but not much for 3rd to 4th. Any help is greatly appreciated. Thanks!

 

Hey Hatten, I am new to this forum (and must admit it's saved me a bundle in DYI fixes so far).

Being a General Motors guy for what seems like ever (i can rebuild a TH350, TH400, and TH700R4 in my sleep), so I have a pretty good understanding on how an automatic works. However, I am stumped with this problem..

It is my understanding that the 722.3 trans uses the cable to determine when it shifts, and the modulator to determine how hard it shirts, correct?

The car is a 1994 E320 with 223,000 miles on the clock. Has the ever-so-slight flare from 2-3. I've done the detent (sorry a GM term) cable adjustment where the two plastic 'points' should be facing each other on the throttle linkage. I tried the modulator adjustment (thought about checking the actual trans pressure at the test port). I was able to almost eliminate the flare with the exception of part throttle where it just kind of 'hangs' there, then shifts.

Now the interesting part...

An old trick on the GM's was to either completely disconnect the modulator, or get an aftermarket adjustable one (or somehow restrict the vacuum a bit). When I plug it off on the Benz, the shifts remind me of a TH350 with a shift kit. Nice firm shifts in all gears, but I know it was never intended to shift like this, and something will eventually break. Assuming the modulator was faulty (not sucking ATF or anything, but obviously not adjusting correctly) I ordered a new modulator, and some goofy pin type thing. When my package arrived, the new modulator (which was a superseded number BTW) had a totally different looking pin included with it, aside from the one I ordered for the old part number modulator.

I am totally confused as to which one to use with the new modulator. Senses are telling me to use the pin that came with it, but it is considerably shorter than the pin that I had ordered.

I have posted a pic to explain this a little better.

I ordered a modulator part# 1262704379, but this is what they sent me, part# 1262709197. The pin next to the modulator is the one that came with it. The brown pin below it is the 1262779375 that was supposed to go with the old part number modulator.

Any ideas??

Help!

Sorry for the huge picture lol

 

hi, i know this thread is old! was just about to start a new one but this might be exactly what the problem is!

just bought a c36 with a 722.3 tranny and the when you change hard from 2nd to 3rd it doesnt engage the 3rd gear! engine just revs away like a false neutral! then when i take my foot off the throttle it engages 3rd. if i feather the throttle it seems to be ok!

so my Q is this the k1 spring do u think? by reading else where i thought it may be a solenoid which has gone bad! i got the car cheap casue of the problem. when i looked there was not enough gear oil in it! im going to use that lucus additive first! or is it a con? bought dextron 3 oil ready for the change! just need to find a filter for a good price.