My Superior Shift Kit thread (W124 300DT)

[jake12tech]

To me the shift kit is just a bandaid until the rest of the trans goes. It is a good bandaid however if you don't feel like R&Ring the transmission at the time. By all means, not a long term fix.

@325K nobody should be complaining about much though. Seen an exception of a 300E hit about 414K before the trans went.

[oilslick]

Still scratching my head here.

[65beto]

Hello MB people! My name is Lou. I purchase a 1995 E320 Cabrio last year with 56K miles on the ODO. But the reverse was lazy both hot or cold start so I figured and oil change was in order. Few months later, I did a transmission pan drop filter oil change with DEXRON 6 fluid. Car was shifting 1-2-3-4 gears great before the service, how ever, a few weeks after the oil change, the reverse takes much longer than before to engage, but only when cold start. After engine goes to normal operating temps, engages fine.

Any opinions would be appreciated.

Lou.

[gsxr]

Originally Posted by 65beto

Hello MB people! My name is Lou. I purchase a 1995 E320 Cabrio last year with 56K miles on the ODO. But the reverse was lazy both hot or cold start so I figured and oil change was in order. Few months later, I did a transmission pan drop filter oil change with DEXRON 6 fluid. Car was shifting 1-2-3-4 gears great before the service, how ever, a few weeks after the oil change, the reverse takes much longer than before to engage, but only when cold start. After engine goes to normal operating temps, engages fine.

Any opinions would be appreciated.

Lou, this sounds like the classic problem with the reverse clutches going out. If the delay is only 2-4 seconds, you can probably live with it for a while. If it's more like 6-10 seconds, you are on seriously borrowed time. If the other shifts are ok, you can usually fix this by pulling the trans and replacing the clutches behind the primary pump, but it's quite a lot of work. There's a detailed thread on the MBWorld forum. A shift kit won't fix this problem, btw.

The thinner Dexron 6 fluid probably isn't helping, but switching back to the original-spec Dexron III fluid likely isn't going to be a magic cure either. Strange that the Dex-6 fluid seemed to make the problem worse.

[Lambrettaman]

I got my '81 W123 300TD back from a vacuum rebuild and a big bad 2-3 FLARE. At least the 1-2 clunk was gone though. After reading a bunch of great stuff here, I decided to try the Superior Shift Kit. Here's how it went for me.

Although a lot you have done this work with the valve body in place, not being at all familiar with this part of the car, I decided to remove mine and work on the bench instead (as the instructions say). Unfortunately, I put my car up on ramps (which are just barely high enough) and drained the transmission before I figured out that I should have put it up higher than that.

Pulling the valve body was easy enough just tedious with the 15 bolts to remove. As long as I had it off, I decided to separate the halves to do the springs that you can't get to without. Separating the 2 halves of the valve body was scary as but it came apart without any tiny balls or valves flying off.

I did steps:

2. the K1 and K2 accumulator control valve springs
3. the end springs in the K1 and K2 accumulators
4. (didn't do this one but wish I had replacing the spring train with the single spring)
7. Replaced the B1 accumulator spring train with a single spring
9. Replaced the TV pressure control valve spring - This one is on the upper body and you get to it by removing the plastic bush which is an interference fit on the big plunger
10. Replaced the spring in the rattling capsule

I managed to put it all back together without losing anything or messing anything up with the help of this video: https://youtu.be/h9thWDLR5yo

That is a great video!

Result? 1-2 is amazingly smooth, 2-3 is a little slow to complete, 3-4 smooth as silk.

PS: I found a link to the service manual that listed 8nm torque values for the valve body and transmission pan bolts and 14nm for the drain plug.

[Hutchinson123]

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

[gsxr]

Tobias,

Remember that the VCV adjustment (on the side of the IP) is not really "adjustable". It should be set via factory procedure and left alone. Adjustments to shift firmness should be done at the modulator on the transmission.

Yes, you can firm up the 2-3 upshift with K1 using different/stiffer springs, mix & match as needed from the Superior kit. You may want to get the 2-3/K1 shift as firm as possible to help even up the difference vs 3-4/K2.

I am not sure about the K2 spring question. The Superior colors are not easy to translate and their documentation doesn't provide alternate means of identification. You could contact Superior directly and ask.

[Hutchinson123]

Dear Dave,

thanks for the input. In general I agree with you. But if you have some gearbox problems due to wear you can "play" with the VCV in order to adjust transmission behaviour.

In fact, if I adjust the VCV factory spec, I get way to hard 3 to 4 shifts and flaring at full throttle (due vacuum modulator pressure). If I increase vacuum at VCV, I can get the same hard 3 to 4 shifts at low/medium but nearly good shifts at full throttle.

It is really a mess that will not end until shift kit installation or better, transmission rebuild...

[gsxr]

The VCV is essentially a throttle position signal. In general, if the VCV requires adjustment away from the factory setting, the engine output may not be normal (either above OR below normal power levels). This is particularly important for turbo engines producing less than rated power, which can cause all kinds of shifting problems that have nothing to do with the transmission. Wouldn't hurt to verify your non-turbo is getting 0-100kph close to factory specs, just in case.

Anyway - as a starting point, VCV should be in factory position, vacuum modulator adjusted to provide zero flare at WOT upshifts, then adjust part-throttle shifts via valvebody springs along with minor adjustments to the modulator. I would only mess with the VCV as a last resort.

YMMV, etc.

[Hutchinson123]

Thank you - I will try it this way.
Grateful to have a vacuum gauge since few weeks.

The engine has now power issues. It reaches 100 kph within factory specs and also achieves top speed of 190 kph (Yes- we can do that in Germany :-) ).

If nobody can help me with the spring issue during the weekend I will contact the superior kit manufacturer and ask them for clarification.
Of course I will share the result here later on.

[Diseasel300]

The VCV on cars with these engines is definitely a "Set it to factory spec, then LEAVE IT ALONE" type thing. If the shifting is still wrong, check that the bowden cable isn't too tight and then focus on adjusting the modulator. My experience has been that the throttle linkage and bowden cable being out of adjustment is a large portion of shifting problems.

[filp]

Hi!
I followed the instructions on youtube as well as from the Superior Shift manual, and pulled the trigger yesterday on my 722.361.

I installed no: 3 (blue end on K1 and single red on K2), 6 (plain finish), 7, 8, 9, + separate bag for stacked 2-3 and 3-4.

Cleaned up everything and filled up with ATF.

Now, it has extremely long 1st gear, then shifts hard to 2nd and doesn't shift higher, even manually.

I'll be taking out those "stacked shifts" springs, K1 and K2 springs, because I didn't really need them, just had early 2-3 sometimes and main reason was harsh 1-2. Hopefully that'll fix it!

If you have any advice, please write. Pressures, bowden and vacuum are perfect.

Besides, I'm not sure about my "accumulator switching on control valve". It is really weird. Looks like version "B" on the attached ATSG picture, but the plastic star plunger has a tiny spring and I swear it came out located the other way. It cannot be placed the other way, so I put it back as pictured. However, the metal piston with hole below (right above gate) had a circular "shade" in the center of the smooth side, so I oriented it the smooth side towards the red plastic star plunger. It seems like that was a mistake.

Update: reoriented the metal piston element (thanks Squiggle Dog for photos!), removed all superior parts except 1-2 shift aaaand it's working again. 1-2 is a bit smoother at partial throttle. Was worth it.