I was having trouble with my 82 240d not shifting correctly so I replaced most every rubber vacuum line on the car. Now it shifts at what I believe is at the right time. How ever when giving it about 1/2 pedal or more it makes neck snapping shifts. If conditions are right it will give me a 2nd gear scratch and in the rain it will fish tail when it shifts. I have not tried changing the filter and fluid yet, could that be the cause? I'm trying to get this car straitened out for my 17 year old new driver. Also the vcv actuator rod is supposed to have a plastic clip that connects it to another rod, mine broke and I'm using ziptyes to hold them together. Any idea of a better way to hold them or where to get the clip?

Thanks,
Mark

Shift firmness is a function of vacuum. Less vacuum = firmer shifts. You may have a bad VCV (Vacuum Control Valve).

So can I check the vacuum going to the transmission at idle and higher revs and see what I've got. If yes does this need to be done with car in gear and moving or can I do it in the drive in neutral?

Do those have an adjustable modulator like the later cars? If so, it's an easy adjustment. I ran into the same thing when I put all new vacuum lines in. Apparently it had been adjusted to compensate for leaky hoses at some point and got pretty soft when there were no more leaks. Firm is definitely better than soft, though yours for sure sounds like too much.

The other thing is what size restrictor(s) are in the lines. If you don't have an adjustment on the transmission end of the line then that's what you'll use to set it.

The only weird thing is that if there were leaks and now there are none, I would expect it to get softer.

-Rog

Here's a link from this site. There are others. It will take a while to get an understanding. Look through the manuals I sent you. They are for newer transmissions but look at the color of your modulator then look up the pressure specs. Specs are similar for a given modulator for most of the transmissions listed.

http://www.peachparts.com/Wikka/TransVacTune Ask Duck Duck Go for "mercedes 722 transmission adjust".

Don't mess with the modulator until vacuum leaks are taken care of even if you have to plug some vacuum lines temporarily to stop the leaks. You don't want to adjust the trans to leaking lines and then have to go back and readjust later after fixing the leaks.

I've read conflicting thoughts regarding adjustments to the modulator without using a gauge. My conclusion is that a newby trans adjuster (ie me) i more likely to screw it up than get lucky and get it right. Just buy a cheap gauge if you don't have one.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

When you say gauge you mean vacuum gauge, right?

I agree with Rogviler and think there is a good probability that someone made an adjustment to the vacuum modulator trying to compensate (trying to correct shift harshness) for vacuum leaks. Now that all vacuum leaks have been fixed would be a good time to adjust the modulator.

You can do it in neutral. The vacuum should be highest at idle and drop as you press the foot feed. This emulates gas engine manifold vacuum, or it's supposed to. Mercedes thus was able to make the same (or very similar) transmissions for both gas and diesel cars.

I 'borrowed' the 4-gauge cluster from a gas car for my diesel and connected the "economy" gauge to the transmission vacuum line. With the gauge I can monitor the vacuum at all times. [The picture was originally intended to show my CRUISE CONTROL indicator but you can also see the "economy" gauge in the left side of the cluster.]

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
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"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

You should have 15-22" of vacuum at idle measured at the main vacuum tube going from the vacuum pump to the brake booster. To get an accurate measurement of vacuum from the vac pump cap off the other lines coming from the main vacuum tube while doing the test. This will eliminate any possible vacuum leaks you have elsewhere in the car giving you a true measure of what your vac pump is actually producing.

The missing clip can be the problem your having .

kick down at pedal ok?these wear out easily what about kick down solenoid attached at the transmission do you have a reading at the pedal kick down switch?

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Carpe Diem!