Tango,

So on the K2 just the smaller spring that goes inside the red spring not to include the white plastic thing onthe other end with the spring, and on the K1 just the purple spring pics. below, top photo of K1 and bottom is the K2.

Chuck
http://img.photobucket.com/albums/v7...s/DSC03453.jpg

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!


:scholar:

DOES THIS apply to ME?!?!
 

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).

:hat:

Look here before you start pulling valve bodies and throwing check balls around
 

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.

Trying to get my head around this...
 

My superior kit just arrived, and I am a bit daunted.

I've read through this thread exhaustively, as well as the instructions from the superior kit and some other threads. Please, please tell me if this is all correct, please, someone:

I have an early, soft 2/3 and flaring, mushy 3/4.

I need, therefore, to replace the K1 & K2 accumulator valve springs, which require the VB to be removed, de-filtered, and turned upside-down before lifting off the lower VB. The separator plate must remain conspicuously in place, against the thicker, upper valve body (now on the bottom) to prevent the loss / misplacement of the check balls. I would do well to drop a few of the 15 VB bolts in loosely to keep the separator plate in place, maybe from the top before inverting the unit onto a clean surface. This modification improves 2/3 timing and firms both 2/3 and 3/4 somewhat.

I will be installing the "normal firm shift" for 2/3 and the "even more firm" for the 3/4, as the 3/4 has always been mushy and 2/3 is soft, but fine in a pinch. For the "even more firm" 3/4, I will be retaining the original small spring coaxially inside the replaced large red spring *edit* for 2 spring trains, pink alone for 3s*edit*. This can be done without pulling the VB, but since I'm doing accumulator valve springs, I still need to pull the VB; might do it best all at once.

Have I got this all correct? I'm not made of time, money, or extra cars, and I want to be certain that I've got the basic idea before doing the driveway backstroke.;)

My advice would be to try the K-1 and K-2 accumulator springs first, since they can be installed with the valve body in place. I found that the accumulator springs had much more of an effect than the corresponding control valve springs.

the valve control spring controls shift timing for the 2/3, no? it's not desperately early...

is there a rule of thumb about which direction, looser or tighter on the bowden cable, corresponds to earlier or later shifts?

At what speed does the shift occur under realatively "unloaded" acceleration?

Increasing the tension on the cable delays the upshifts.

I believe about 2500 - 3000, but I will get back to you tomorrow...

Thanks, that's what I thought.

the paint on the springs
 

Would it behoove me to wipe the colored paint from the springs in the kit before I install them?

I'm going out to get the ATF to replace right now, and I was hoping to install the large springs today as a start...

I thought the paint on the springs helped identify them...? If so, I'd leave the paint on. If not... nevermind.

:hat:

They do, Dave...
 

The colors are referred to in the instructions. I am a one-step-at-a-time kinda mechanic, and as I have never ventured into replacing transmission parts, I only pulled one plate at a time.

I did soak the paint off in kerosene first, however, then ultrasonic-ed them, dried, them well, and lubed 'em up with ATF. I figure the less particulate crud, however microscopic, the longer the tranny life. If I had pulled the VB or done any of the B-springs, I would have done it, too, just slowly, carefully, and methodically...All the OCDers know what I mean...

Replacing just the K1 and K2 accumulator springs has fixed the problem. Like magic. What an easy job...an offset hollow-ground flathead, a 13mm ratchet, and a 5mm allen head. Lather, rinse, repeat...

Third runs up to about 4200+ now, however...I THINK that should be normal at WOT, but there's no more rubber smell on highway 3/4s, no neck-snapping shifts, and the vacuum is turned all the way up to 13hg inches...

Thanks for all the help, everybody, some posthumously. I'll report back on the new 0-60 run later tonight!

Besides K1 and K2 springs , which others can I replace with the Superior shift kit springs without pulling the valve body ? - Tahnks

The B-1 spring train, on the front of the valve body. Everything else requires removal of the valve body. There are several springs that can be installed without separating the halves, but access is blocked at the rear with the valve body in place.

Removing the valve body is not much of a problem. Separating the two halves is another story.

I can email you a copy of the kit instructions if that would help.

I’ve had my 300D long enough now and am comfortable enough with it to start tackling the shifting issues I am having with my 722.4 transmission. Rather than starting another thread, I am hoping that continuing this one will go further in documenting corrective actions for the 722.4.

These are my symptoms.

Cold Engine and Transmission-
Light throttle, Harsh 1-2 shift at high rpm, Flaring 2-3, 3-4
Heavy throttle, Good shifts all gears.

Hot Engine and Transmission (maybe 15 minutes of driving)-
Good shifting at all loads and RPM ranges, no complaints.

I have replaced the filter and fluid but this shifting pattern stayed the same.

I plan to follow gsxr’s recommendation of verifying the vacuum system first. First I’ll replace any bad tubing and then check/adjust the VCV according to the FSM.

The FSM states that the vacuum should be 420 mbar for my 602 engine application. Am I correct that higher than the spec can cause flaring?

Also, I don’t understand the comment “When engine is switched off, move accelerator to full-load stop. Specification: 0 mbar …”. Wouldn’t the vacuum drop to 0 on its own once the engine is off?

Thanks for the help!

The step assumes you have an external vacuum source attached to the VCV. The VCV vacuum supply port should be isolated from the output port at full load stop. If you use a Mityvac on the supply port, a vacuum gauge on the output port shouldn't respond.

Sixto
87 300D

Sixto is exactly correct. You need an external vacuum source if you want to measure readings with the engine off, and you really don't want to do this with the engine running, unless you don't mind having your hands and face right on top of a motor spinning to 5000rpm (personally, I don't like that).

I use a venturi-type vacuum "pump", about $15 or so from Harbor Freight, but this requires a compressed air source to power it. Otherwise, a second vehicle (gas or diesel) will work for a vacuum source, just get a 10-foot length of vac hose from McParts, and hook it up to the other car to get a steady vacuum source.


Also - the FSM specs in mbar are kind of a pain to decipher. If you provide 15" (or more) of vacuum into the inlet of the VCV (located on the side of the IP), the output should measure 12-15" (approx) with the throttle at idle position, and this should smoothly decrease to zero vacuum at WOT. At least, that's what I measure on my cars, and mine all shift normally...


:blink:

I get it now. Thanks for the explanation. I do have a MityVac that I will try to use. The tip about the vacuum pump from Harbor Freight might come in handy if the MityVac doesn't have enough volume.

The MityVac won't work. The VCV operates by bleeding off vacuum at a controlled rate... the MityVac simply can't produce enough volume. Either the HF venturi pump, or a second vehicle, will be required to supply the vacuum. Or, you can do it with the engine running.

Another option is to connect a vac gauge to the output of the VCV with a long length of hose, so you can view the vacuum while driving the car. And also disconnect the kickdown solenoid at the back of the tranny, and the Bowden cable. That will allow you to move the throttle between idle and WOT while driving, without the transmission downshifting.

:boat:

Quick question here I hope. I have a 420SEL and after reading this thread and other sites I ordered the Superior kit. I pulled the valve body today and started replacing the k1 and k2 springs. The k1 went with no problem, but the k2 has an issue. The designated springs in the instructions will not fit inside the accumulator. I sent an e-mail to where I ordered the kit from but thought I would check here as well. Am I missing something. The way I read the instructions, the pink spring should replace all of the other springs and plastic parts except for the accumulator itself. Is this right? TIA

The instructions call for using the red spring in "late models."

Did the original configuration consist of two springs or three springs?

I was under told this was an early model but I could be wrong. It had three springs in the original configuration, however it didn't have any of the plasitc internal pieces.. I'll check to see if the red spring is narrower. However, the shorter blue spring still doesn't fit inside the accumulator. Thanks for your help.

I did go ahead and assemble it using the red spring and the original shorter spring in place of the short blue one. Unfortuneately once I got everthing together the transmission will not engage in any gear. Still checking it though. TIA

There is a slot in the shift plunger that must be engaged when the valve body is reattached to the transmission.

Tangofox007,

Thanks. Wouldn't you know it. Do I need to pull the valve body back off to do this? I'm assuming I do have to pull the pan again.

Yes.

Thanks for the input. Well the good news is I finally got the drain plug out. The allen wrench slot was a bit stripped and I had to work on it a bit. So once its drained I'll pull the pan and then take the valve body down again. I have looked through my books but can't reall find any refrence to doing this. Can you provide any hints? TIA

The shift plunger on the left, rear side of the valve body has a notch or groove which needs to be engaged (mated) with the shifter mechanism as the valve body is reinstalled. If you didn't do that previously, it is possible that the plunger was damaged as the valve body bolts were tightened. Also make sure that the throttle plunger aligns with the cable bellcrank on the right side. (That usually takes care of itself.)

I recommend that you verify proper shift mechanism operation before reinstalling the pan. (Have a helper move the shifter while you observe from below.)

Thanks for the info. I have the valve body back off and will see how it looks. Thanks again.

OK, I've located the plunger and the shaft part that I think should move it. I've got the body back in place and the plunger does move as you move the gear lever. However, it moves from park to R to D to 3 to 2 to 1 with no problem. But as you move the elector back to P the plunger does not move back. Is this possible becuase there is no pressure against it since the car is not running? TIA

OK, put fluid back in and started it up but with the same results. I don't have a good picture of the part that mates up to the shifter part. But it's plastic and has kind of a l shape to the piece that appears to mate with the pin which sticks out of the shifter piece. Its hard to tell if this is broke or not but I'm thinking that this should probably be a U shape so that the pin pulls it in both directions. I don't know if you can buy this piece or not but I'm thinkking it might be better to buy a complete new or rebuilt valve body. I'm probably going to sleep on it tonight and do some more reasearch. Please pass on your thoughts. Us retirees need to stick together. Thanks for your help.

Yes, the selector valve should be positively engaged in both directions. My recollection is that it is possible to install the selector valve upside down. Or possibly 90 degrees off. Is it possible that that occurred? The valve is indexed by a long groove on the valve and a projection on the retainer plate.

I had not removed the selector valve from the body, just the K1, K2, and B1 springs. So it is in the same position as before. But thanks for the suggestion. I'll see if I can find a good picture of one and compare them. Thanks again for all the help. I'll also try and get a picture of mine and post it. Have a good Sunday.

According to the EPC, the selector valve is available as an individual part.

Thanks. I havn't been able to find it online anywhere. But still checking. Do you have any suggestions on who might have it? TIA

I would not expect to find it anywhere except a MB dealer.

Is it possible that you did not get the valve plunger properly engaged with the shift mechanism? If it was slightly out of position, it would be possible for it to push but not pull, or vice versa.

My experience is limited to a '82 300D. Yours might be different, but on mine it was quite obvious how the parts shoud mate. There was a sort of "receptacle" on the rear of the plunger that snapped over an inverted "T" on the shift mechanism.

I am checking on ordering the part now. I have some pics I took of the valve body. The system won't let me add them for some reason. So if you're interested pass an e-mail address and I'll send them to you. Thanks for the help.

broken valve slide
 

OK Craig,

In case you haven't resolved this: I did the same thing. You will need to replace the entire valve (metal slide, nylon end slot adapter thing) for about $30 only from Mercedes. As soon as you moved the shifter lever without the correct registration, you broke off part of the nylon.

Superior kit
 

Well I think that a company that sends out a bag full of colored springs for a transmission that costs $56. with no instructions shuldent call it a superior kit.

I put thge purple in the K-1 and then the short blue on the end of the K-2 three spring train. The 1-2 shift is on time but still shifts hard. The 2-3 flair is fixed compleatly so I am happy

If I want to get rid of the 1-2 slam what do I do next??

Please stop bumping all of the Superior kit threads is what you should do next. If you think you can design a better kit for $55 or less, let us know.

After that, call them on Monday for a better copy of the instructions. Again, my copy was perfectly legible and easy to follow.

There is a spring in the kit for that issue. You will need to remove and split the valve body to install it, however.

I have a '88 300TE. It starts out in 2nd. Only goes to first if I floor it. Is that normal? What is Late vs Early model? It looks like that is determined by how many springs are in the stock accumulators?

If my starting out in 2nd is not normal, How do I fix it? It seems like it is correct the way it feels.

Because it starts out in 2nd, that made me originally think my problem was a bad Flared 2-3, but it is actually a Flared 3-4. I figured that out by moving it manually into third after the flared shift and it downshifted.

So I don't really have a 1st gear unless it is floored.

Depending on the model year, yes, some cars start in 2nd gear. It sounds like this is normal for your '88 300TE. I believe you can make it start in 1st gear at part throttle by moving the shift lever back to "2" or "L" when at a stop light, waiting a second or two, and moving it back to "D". Then it should start in 1st gear without flooring it, just for that one start. At any rate, if it doesn't bother you, I'd leave it alone...

:batman:

Thanx! Yeah it really feels like it should be this way.

I put the K1 and K2 accum. springs in. Shfts are greatly improved, but I do have a question about shift quality.

Can you guys run down what you mena by Flare, soft mushy, slow, etc?

Mine on 3-4, would act like a slipping clutch on a manual tranny. The rpm would increase without the car going faster and you would naturally lift and let it shift. I thought that was a flare.

Now it shifts firmer, but I feel a little "snatch" when it shifts and if there is any "flare", it is minimal if at all. But now I'm not sure if I should try the control valve springs?

So that brings me to a descriptions of what the terms mean and what is perfect?

The first problem I am having with this kit is lack of experimental data.


How is a professional (the kit is sold to them) supposed to diagnose the transmission issues if he hasn't spent the time in the vehicle?

I began installing this kit but quickly realized I did not know enough about the behavior of this trans to install it.

It seems rather ridiculous to go replacing springs without any info, right? I only have a few trips over 6 months ago with this vehicle.

Are there any suggestions about worthy replacement items without 'knowing' the issues?

You need to know precisely what problem(s) you are attempting to solve before you install any of the kit components. At least that is what my "experimental data" suggests.

The concept known as a "test drive" comes to mind.

what is done to a transmission on a bench? Lots of guessing?

...but I agree. just disturbed.




it certainly appears there would be a dearth of "experimental data" after a few test drives.

Well, most Transmission guys don't have advanced degrees from Cambridge.

They drive the car, they hopefully listen to the customer and ask questions. They rebuild and install kits, in a half assed method in respect to MB transmissions in my experience.

if you bring you trans to a shop as a core, there must be some standard for rebuilding it. They aren't going to know @&*^# about it.

And a service manager is going to listen to a customer who doesn't know what the heII he is talking about, and make some guesses?

weak.

They do listen and ask questions, ie

It doesn't go into reverse

It shifts slowly

It is missing 4th gear

it slips during shifts

A good diagnostician should know how to ask the right questions to get answers.

The moral to the story is, if the shop is not known for doing MB trannys, you are wasting time and money. And you'll be doing it again in the near future.