My Superior Shift Kit thread (W124 300DT)

[diesel_fan]

Thanks for this and Bowden cable thread, Bob!
I am about to go through all these steps, that you did, to fix my tranny issue.
Is superior kit includes K1 kit?

Regards,
Diesel_fan

[bob_98sr5]

In the documentation I posted above, the tech support # is outdated. It is 850-575-7877. In the documentation, they keep saying "Early 722.3 vs. Late 722.3 adn 722.4". I called them about that and they faxed me these two docs that clears up the confusion. Trouble is, you have to remove the valve body to be 100% sure!

I'll post all the docs that came in the box later tomorrow.

[bob_98sr5]

Originally Posted by diesel_fan

Thanks for this and Bowden cable thread, Bob!
I am about to go through all these steps, that you did, to fix my tranny issue.
Is superior kit includes K1 kit?

Regards,
Diesel_fan

Diesel,

What's great about this kit is that it covers all the common problems throughout each gear transition (1 to 2, 2 to 3, and 3 to 4). So in order:

B1 accumulator: 1st to 2nd
K1: 2nd to 3rd
K2: 3rd to 4th

So i spent about an hour fine tuning it. I took the wife out to dinner and we took the Benz. She was really impressed that the shifts do not hold on at high rpms and then slam into the next gear. She hates this more than anything, so she was very pleased on the drive tonight.

When you work on this, shoot me an email and I'll help you as much as I can. I'm going to try to write a transmission reconditioning writeup soon before all of it escapes my memory (which is really short!). I took alot of pics, so that should be a big help too

[bob_98sr5]

Here are the docs. 2 of them are on 11 x 17 paper.

[jfowler]

Bob, have you checked the vacuum signal going to your transmission? After reading your blog I wondered if you hadn't turned the blead off valve adjuster too much.

-Jeb

[bob_98sr5]

jfowler,

yes, you are definitely right. i am sure I did and i am going to do some vac tests this weekend. I have to find my vac pressure gauge in my garage---been meaning to do that for a few weeks now.

[tangofox007]

Originally Posted by bob_98sr5

Here are the docs. 2 of them are on 11 x 17 paper.

Did those four pages come with your kit? I just received my kit in the mail; the only instructions that were included was the page on "stacked 2-3 shifts."

As I had everything disassembled and ready to go back together, the lack of instructions is more than a little irritating. If I could only read the fine print of the bottom of the fourth page, I might be good to go.

[bob_98sr5]

Tango,

there were 2 docs only, both double sided.

Check your email.

Bob

[gsxr]

Great info, thanks for sharing!

Now, I may be a little late to the party... but one major item has been overlooked here. The transmission shift point (controlled by the control cable) and shift firmness (controlled by the vacuum signal) on the 1987-1993 300D are based ENTIRELY on throttle position. Why is this critical? Because if your engine power output is below normal (due to ALDA issues, or any of a dozen other reasons)... the tranny will shift like crap (often a late, high rpm, harsh shift). But there may be nothing at all wrong with the tranny, or springs, or anything else. Fix the engine power output, and the tranny problems may go away.

Also, make sure the VCV on the side of the injection pump is set correctly. This is not a "seat of the pants" adjustment, there is one proper setting, and you don't tweak it either way. (It can cause weird shift issues if this is mis-adjusted!) See the FSM for the official procedure (click here), but basically you loosen the mounting bolts, have a helper press the pedal to the floor (or pull the throttle cable to WOT), gently rotate the VCV (from full CCW turn it CW) until resistance is felt, then tighten down the bolts. Often it ends up right in the middle of the adjustment range. This is the FIRST step in correcting diesel tranny issues. The second step is making 100% sure that all the Tecalan vacuum tubing is intact and not leaking, along with checking the rubber fittings. Replace anything that is cracked, brittle, soft, or otherwise questionable. Then you have to fix the engine power output, particularly the off-idle power (generally fixed with ALDA adjustment).

When everything is set correctly, the transmission shifts should be butter smooth cold or hot, at light or medium throttle, with zero flaring. At WOT (kickdown) the shifts should be firm, and should occur at 4800rpm for each up shift. My '87 tranny has 300kmi on it, with all the original "K" springs (no Superior kit needed), and it shifts perfectly. But I've also spent a lot of time getting the engine power delivery correct (0-60 in 10 seconds), setting the VCV to spec, and replacing every vacuum tube & rubber hose in sight.
It's a good idea to replace all of the old fossilized stuff.

Hope this helps!

[iandiam]

Originally Posted by gsxr

Great info, thanks for sharing!

Now, I may be a little late to the party... but one major item has been overlooked here. The transmission shift point (controlled by the control cable) and shift firmness (controlled by the vacuum signal) on the 1987-1993 300D are based ENTIRELY on throttle position [...] Fix the engine power output, and the tranny problems may go away.

Also, make sure the VCV on the side of the injection pump is set correctly. This is not a "seat of the pants" [...] but basically you loosen the mounting bolts, have a helper press the pedal to the floor (or pull the throttle cable to WOT), gently rotate the VCV (from full CCW turn it CW) until resistance is felt, then tighten down the bolts. Often it ends up right in the middle of the adjustment range.

Dave,

Does this apply at all to the 617 VCV configuration as well, or just the six-cans? I'm replacing my modulator today (it's leaking down in seconds,) and hoping that the spring on the old one is broken, as I have the most erratic shifts one could imagine, with lots of unpredictable flaring and the occasional case of whiplash. I can't seem to adjust the modulator for firm shifts (or at all.)

I have never heard of this and can't find [ed:doesn't mean it's not there] any reference to this in my FSM, but it's one of those PDF ones where the search function doesn't want to work...

[gsxr]

Originally Posted by iandiam

Dave,

Does this apply at all to the 617 VCV configuration as well, or just the six-cans? I'm replacing my modulator today (it's leaking down in seconds,) and hoping that the spring on the old one is broken, as I have the most erratic shifts one could imagine, with lots of unpredictable flaring and the occasional case of whiplash. I can't seem to adjust the modulator for firm shifts (or at all.)

I have never heard of this and can't find [ed:doesn't mean it's not there] any reference to this in my FSM, but it's one of those PDF ones where the search function doesn't want to work...

Basically, yes, it does apply to the OM617 as well... although the injection pump and VCV are different (the adjustment procedure is NOT the same as the 60x VCV), if the engine power delivery is wrong, the shifting will be wrong as well. The 61x setup also determines shifts based on throttle position.

Although I couldn't find anything in the 617 FSM specifically related to the VCV, check out this PDF for adjusting the throttle linkage... it may be of some help.

FYI - I updated the previous post with a link to the OM603 procedure for adjusting the VCV (this obviously won't help for the 617, though).

[iandiam]

Originally Posted by gsxr

Basically, yes, it does apply to the OM617 as well... [...] if the engine power delivery is wrong, the shifting will be wrong as well. The 61x setup also determines shifts based on throttle position.

Thanks, Dave. This is all good stuff, and I'm glad to see people pointing out the relationship between power output and trans function. I first noticed when I replaced a plugged filter and the trans started behaving badly - readjusted all the linkages, VCV and mod, to better ends. It seem that the mounting bolts have little to do with this particular configuration - always smart to ask an expert, though.

In the process, I have found that my modulator spring was no longer adjustable - the stop on the end of the spring had rusted through, and the adjuster was nonfunctional rendering the adjuster useless. Mod replacement eliminated the 2/3 flare completely, so to those of you who say "wouldn't a bad mod produce hard shifts?" I say NOT if the spring is shot.

Look here before you start pulling valve bodies and throwing check balls around the garage..http://www.peachparts.com/shopforum/showthread.php?p=2144030#post2144030

I could still use an updated K2 spring train, I think, still a little mushy on the 3/4.