My 82 240d will rev real high before it shifts when it does it's a hard shift, jerks you back in the seat, other times it will shift almost immediately from 1st to 2nd and 3rd to 4th. When it's doing the high rev one if I lift my foot off the gas then reapply it will shift ok. I've looked at the vac lines and there are non disconnected that I can see. Does anyone have a diagram of the vac lines so I can make sure that everything is how it should be. If everything is set up right is there a way to adjust the shifts?

Another ? When I bought this car about 3 years ago I replaced the shift rod bushings because they were worn and not engaging park all the time. I still sometimes have to push the shift lever towards the dash to engage the park safety switch. This isn't a problem for me but my wife wants it fixed before my son to be 16 year old son starts driving it. I'm guessing this is just the rod needs to be adjusted or is it something else?
Thanks for everyone's help.
Mark

You are correct to check the vacuum lines, as your car most likely has the .117 transmission, which uses an internal governor to control shift points (as opposed to most others, which use a control rod or cable from the throttle linkage as well) and vacuum to control shift quality and final timing.

What you describe is late shifting and "stack shifting" and in addition to looking over your lines, you should try adjusting your vacuum control valve (VCV), the white-yellowish module on top of your injection pump.

Here is the DIY:

Transmission flaring or clunking? VCV DIY - Mercedes-Benz Forum

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Thanks Zachariah's, it's raining today but if it's clear tomorrow I'll look at the VCV valve. Is that the only adjustment that there is to make on a 240d as far as the trans goes?

You can also adjust it at the transmission. There is a screw inside the modulator. You need to check for vacuum at that point, and that the valves diaphram is good. If you adjust on the point at the injection pump, you need to just do very small increments as it will go wayward if you don't.

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Rebe

What should a vac gauge read at the modulator? So am I understanding it might be better to start at the modulator?

Just so there is no confusion, those two adjustments are not the same.

Adjusting the modulator on the side of the transmission affects shift quality because it acts on the internal operating pressure of the transmission. There is some debate over whether (and if so, how much) it controls shift points as well, on these particular vacuum-control transmissions.

The modulator cannot be the cause of one shift being held, then others stacking. You can adjust the modulator to shift late (hard), or early (soft/stacked) but it cannot cause both symptoms at once.

In contrast, the VCV bleeds off vacuum at shift points and has no direct link to transmission operating pressure. If it is not working, the modulator continues to receive full vacuum and will typically hold the 1-2 then possibly stack the 2-3 immediately.

There is no need to be cautious in the VCV adjustments as you are tightening a spring. As I recall when I did mine, it took four or more turns to get it comparable to the tension on my other (much lower mileage) car.

You have to make sure that everything is in order up top in the engine compartment, before messing with the modulator (apart from testing to see if the black line going to the modulator is holding vacuum). I would suggest you proceed:

1. if your transmission fluid is old, change the fluid and filter.
2. check the vacuum hoses and all the rubber joints/splitters for breaks.
3. check that the white crossover lever valve(s) are working correctly (different models and years have different layouts of these).
3. adjust the VCV.

Let us know how if this helps and at that point, based on symptoms, possibly mess with the modulator.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Did you replace the shift rod bushing and the shifter bushings? There are 4 that need replacing.

Have you tried to unplug the kick down switch under the accelerator to see if that cures the issue?

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I think I replaced all 4 I'll have to check that out. No I haven't unplugged the kick down switch. Didn't think of that being the problem because it drops the car a gear when I floor it.

Come to think of it I only remember cussing like a sailor twice when replacing the bushings. Hope I didn't offend any sailors.

The kick down switch can stick and cause your issue, it is always good to unplug it and take a test drive...its an easy diagnosis item.

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Unplugging the kick down switch made no difference.

Before you endlessly adjust stuff and never get it back to where you started...
Put a vacuum gauge on the transmission at the modulator, with a tee and drive the car, it really helps to have a passenger at this point-one to drive and one to watch the gauge and notice what is going on. There is a good write up at Continental imports on how the vacuum system works, bleeds and such.
You can do all the adjustments you want, but if the vacuum is not right (as in sudden changes) it will still cause problems. Looks for leaks/cracks in the tee fittings, look at the throttle controlled bleed on top of the valve cover. A mity vac will come in handy for all this also.
It helps to know what is happening vacuum wise BEFORE you make any changes.
These are the kinds of repairs you really need to educate yourself on and take the time to understand, it is highly unlikely any shop will. Step one for transmission related issues at the one specialist I know is replace transmission with dealer reman unit...then figure out what else is wrong afterwards! All at $110 an hour.

Second the need to do it yourself. There are very few shops that know how to address vacuum issues on these cars.

If the vacuum issue is affecting your brakes, step #1 is to replace your booster, for most of them. $$

If the vacuum issue is affecting your door locks, step #1 is to replace your vacuum pump. $$$

If it's affecting your transmission, as noted, replace or rebuild it! $$$$$$$$$

When in the end it could just be a leak somewhere...which fixing yourself is ¢¢

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My 1984 300D is essentially behaving the exact same way (albeit intermittently). I also suspect that the vacuum system is the culprit, as the car shifts fine when it feels like it (which is now most the the time, thank God), as well as under full throttle. If I somehow manage to get to the problem before you do, I'll post my findings here. If not, I'll keep a close eye on this thread and leech as much information as possible for my own troubleshooting process.

Good luck!

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Just be aware that there is a fair amount of difference between your transmission and his. Your transmission has a Bowden cable that controls the shift points, his does not.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22