I'm starting to have some flaring (2-3) on my 1983 300TD, and I'm doing some reading about vacuum leaks, amongst other things. One thread mentions removing the "flippers" on the top of the valve cover, saying they're not needed. I'm reluctant to start removing parts without knowing what they're for.

I'm assuming the black plastic vacuum line that dives down towards the tranny at the rear of the engine bay is the line that goes to the vacuum modulator on the transmission? I guess I'll need to jack the car up to get underneath, to check the condition of the rubber vacuum hose at the attachment point..I suspect it's probably rotted and leaking. But, if I replace it and still have flaring, I need to know where else to check for leaks.

Along with the recent 2-3 flare-which occurs after the car has warmed up and especially after a highway run when returning to local streets-I've always had a somewhat hard 1-2 shift, particularly when cold. I don't know if there's a connection. But the 1-2 was really only noticeable in very cold weather (single digits to high 20s) for the first couple minutes of driving, when the car was very sluggish and basically had to be floored to move away from a stop at a reasonable speed. So the hard shift was occuring at fairly wide-open throttle settings.

Currently, when the car is warmed up, the 2-3 flare occurs only during moderate throttle; if I'm accelerating hard, the tranny shifts normally from 2-3 (no flare) although I'd say it's a fairly gentle shift/certainly not firm. Also, if I'm accelerating *really* gently (old lady style) it shifts normally.

oh..another possible clue-at the same time the flaring started, I noticed that once the car was warmed up it tended to start in 2nd gear unless I pressed the accelerator pedal pretty far down. So maybe this will give someone more ideas...

Trans fluid is about 1/4" above the top line when *really* warmed up..I plan to suck a bit out with a hand pump, but I doubt that's the issue because I haven't added any fluid since I've had the car and it's been fine till the last couple of weeks. Fluid was new when I got it 2 years ago and is still clean/fresh.

I can post a photo of the black plastic vacuum line in question, in case it helps...but I suspect anyone familiar with this issue will know which line I'm talking about.

When I have had vacuum leaks (vacuum pods under the dash), my car shifts very hard. I successfully addressed my flairing shifting by adjusting the VCV valve. I found stuff on how to do that by searching this forum.

You can adjust the VCV (I have done so on my '81 300SD) but I would only do that as a last solution. Work off the plastic dome gently with pliers; it is just a press fit and does not screw in. The adjustment is done by turning a small nut; recommend you do this in one quarter increments. However if it has worked properly all these years, I will bet it is still adjusted properly; mine was after some 35 years.

In regard to the hard upshifts - the TD is not bleeding off vac fast enough. You need vac for smooth downshifts but it is designed to bleed off the vac very quickly for upshifts. At wide open throttle (WOT) there should be zero vac going to the tranny for a smooth shift. My SD vac goes from 14ihg to zero almost instantly when I hit the accelerator and therefore I get smooth upshifts. If you are attuned to your engine, you can help it shift with a gentle foot on the pedal.

Since I do not have a TD, I do not know about the flippers. But I would hesitate to start removing things.

Not sure whether this could be a K2 problem but there is a chart which shows which are involved in any shift. Will see if I can find and attach the chart.

Found the chart:

Moderator - maybe make this a Sticky?

"The flippers" I am guessing that someone is speaking of the little valves up on top of the valve cover that has little levers (all the ones I have seen are white plastic).
When the little levers wear our the plungers in the valves can protrude too far and create a vacuum leak.
Don't know if they still sell them but it used to be you could buy the little levers as a separate part. I did that long ago.

If your Engine does not have an EGR I don't think you have those little valves.

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84 300D, 82 Volvo 244Gl Diesel

I removed mine,as I could not find anywhere the S shaped hoses for it.They had turned to dust.Just ran one line to trans modulator,another to do hickie on ip. I removed my alda for better power.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

thanks for the info so far...honestly I’m more concerned with the 2-3 flare than the firm 1-2 shift.

what is the VCV mentioned in one or two of the replies? Is that the vacuum modulator down on the transmission? (I’m assuming it’s down there). I’m reluctant to start “adjusting” that, cause like someone mentioned it was shifting fine till suddenly the flare started.

A few things are already disconnected on this car-the pneumatic door locks, for instance. I don’t have the patience to try to figure out why the PO disconnected those lines, and I don’t care about having the doors lock with vacuum. I just want the tranny to shift the way it should.

No. VCV is vac control valve and it lives under the hood near the injection pump. It is basically white plastic with a dome and has vac lines attached. As I remember the VCV is what bleeds off vac when you hit the throttle; this lets the tranny upshift without a clunk.

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ok..thanks to all. Will update once I get into it...weather is miserable and I live in an apt. building (no indoor parking or garage).

? Is there a link to how to remove this and what to adjust ? .

Once that white plastic turns yellow it gets *very* brittle and I don't want to break it...

TIA,

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Following with intrigue! My '81 300TD has the same flaring issue, but only when cold (as in engine / transmission, not ambient temps). Shifts quickly from park to any gear, and under light to moderate throttle, flares from 2-3 and 3-4 (sometimes). Under moderate-heavy throttle (I try to avoid this on a cold engine generally), it's normal. Downshifts in any situation are perfect.

There are service records going back to new for this car, and the first one I can find with this complaint is from the early 90's. The car has been driven over 100,000 miles with this condition, and it appears nothing has changed.

So, I just keep driving it, as is. Problem goes away after about 5 minutes.

I'm going to check out these so-called 'flippers' though, and see if they are leaking.

Thanks, All.

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Filmmaker, Dad, Citizen of the World in Asheville, NC
=== current vintage stable ===
'73 VW Thing, '09 BMW 328i Convertible, '07 Honda Ridgeline, '94 Chevy Step Van