Dear Benz drivers,


sorry for jumping in here but I have a question regarding the shift kit.
Just received it this week (shipped from the US to Germany) and want to install K1 and K2 accumulator upgrades within next week.


Vehicle: Euro 300 D OM603 with 110 hp and 722.415 transmission





I want to go for step 3 of the instructions only.
For the K1 it's quite clear - just replace the end spring of the original K1 by one of the two small blue springs. I have already installed the reinforced K1 option from MB so I will add the blue spring to this one.


The main question is:
My 2-3 shift is really nice, firm (not hard) in all throttle positions.
The 3-4 to shift is quite hard. If I adjust the VCV completely counterclockwise direction, I can get "okay shifts" from 3 to 4 (could be better), but then with light throttle I have again the rpm increase at 2-3 due to worn clutch pack. At more throttle it is fine again.
Furthermore with various VCV and modulator adjustments I can get acceptable 3 to 4 shift under light throttle and also acceptable 2 to 3 shift but then under full throttle 3 to 4 engages hard first and then it takes one or two seconds to fully reduce rpm to higher gear (I think you call this flaring). So in general: Both shifts are completely unbalanced and I have already spent hours and hours to get an acceptable setup but it won't work.
Vacuum system and VCV are checked and various hoses replaced - no issues on that side.


So my plan is:
Add the blue end spring of the superior kit to the reinforced factory K1 accumulator, hoping for a better pre-load in order to avoid slipping from 2 to 3 at slight throttle so I can increase vacuum in order to have good 3 to 4 shifts at light or medium throttle (Currently they are hard/harsh).


In addition to that I also want to replace the original K2 spring (I have the 2-spring version) by the superior kit spring that is described in step 3 of the kit.
I am hoping to reduce harshness on the 3 to 4 shift and flaring at full throttle when I reduced the vacuum.


Hope this will work. I was also very suprised that the reinforced K1 kit not only reduced/eliminated 2 to 3 slipping but also made the shifting smoother (no harsh kick that I had sometimes before). This experience makes me hoping for the same result with the 3 to 4 shift with the stronger spring.
Then even if I only try to adjust 3 to 4 shift with vacuum only without considering 2 to 3 performance, I get hard shifts at low/medium throttle or "acceptable" (not satisfactory) shifts at low/medium throttle but flaring at full throttle - this is a mess.




However, here is my question:
The Kit instructions states that you should replace original K2 springs by the single red spring in the kit. But I have two red springs in the Kit.
One in dark red/rust with thicker material but less coils and one bright red (orange) spring with thinner material but more coils.
Which is the correct one for the K2 step 3? The Kit only describes one red spring, not any orange, bright or dark red spring.


Please see the following photo:
Top: Original K2 accumulator with springs
middle: dark red "thick" spring
bottom: bright red "thin" spring




I am tending to the thin spring because it can be compressed by the fingers but definetly has more pressure than the original spring. Could be good for more "precise" shifting results!?!

The thick spring is really stiff. Compressing with the fingers is nearly impossible and in comparison to the original spring it seems to be whole lot too stiff.


Can you help me with this issue?


Thank you very much in advance for your patience and sorry for the long text which my contain various spelling mistakes...


Greetings from Germany



Tobias