I was very low on power so I adjusted (lengthened) the linkage to the injector pump. I have a substantially greater amount of power now and do not want to lose it.

Now, I effectively have no 3rd gear and very light flare from 2-3 and 3-4. I still have sooth down shifts. Had hard upshifts prior to the adjustment. Vacuum lines were not touched or loosened/disconnected.

If I am light on the throttle, I can keep it in 3rd for a few seconds. If I am on the throttle I essentially shift from 2nd to 4th, but still have a quicker vehicle than before I adjusted the linkage.

A side note, for the last 3 years there is sometimes a 10 second delay between reverse to drive.

Can I adjust other rods in the linkage to get things back to normal?

What car is this? Year and model matters, there are a couple different transmissions out there and their adjustment procedures are different.

The very long delay from R to D suggests the transmission probably isn't long for this world. Have you checked fluid level? Have you checked it correctly? (transmission up to temp, engine running, on flat and level ground)

You can try adjusting the vacuum modulator to firm up the shifts a bit and see if it stops the flaring. If it wasn't flaring before your adjustments and is now, firming things up a bit may help. The transmission shouldn't be silky smooth, you should feel the gear engage, but it shouldn't be rough or violent.

Assuming you have a 1983+ year model, you should have a bowden cable on the throttle linkage (location depends on year and model). Tightening it up a bit will raise your shift points and let you hang in gear longer.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Would help if you would tell us that it is a 1984 300D. That way we do not need to look it up in your profile.

Sorry guys. I thought I had a signature.

One of the things to check for, especially if you've "modified" the vacuum to the EGR, is the metered orifice. It's located at #63 in this vacuum diagram on about page 7:
https://www.startekinfo.com/StarTek/outside/12253/program/Engine/617/14-050.pdf

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

I'll check after work but I believe that orifice is there. EGR is deleted. Over-boost bypassed. Alda gone. Switch over valve is gone.

And before anyone jumps to a conclusion. It's been that way for over 60k miles. All I did was make increased the rod the injection pump length.

Now no 3rd acts up. But with the power improvement, I will keep it as is if I have to.

If you're flaring/slipping, you won't be dealing with it for very long. Best to adjust things to fix the problem.

Tighten up the bowden cable, adjust the modulator and see where that gets you. To test the modulator theory, disconnect vacuum to the modulator and go for a drive. If the slipping/flaring goes away and your rough shifts return, you know a modulator adjustment is on your shortlist.

If you still have extremely crappy shifting from 2-3 or a "stacked" 2-3-4 shift, consider replacing the K1 accumulator spring in the valve body. Part is under $10 and is very much a DIY job (search the forum for a how-to and part number).

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Agree; drive it around the block with the VAV line disconnected. You should get smooth upshifts because it needs little to no vac - but you should get harsh downshifts. If that is the case, an adjustment to the vac modulator might help. As I remember you click the vac modulator clockwise for tighter shifts.

Vacuum disconnected to the modulator will also cause extremely abrupt/harsh upshifts at low throttle inputs as well. The modulator is supposed to soften those shifts to make it tolerable, without the vacuum input, anything that's supposed to be softened will be rough/harsh.

If the transmission is still slipping/mushy with the vacuum disconnected, there are deeper problems.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Diseasel - that is not my experience. I tested this with my '81 300SD. With no vac the tranny upshifted perfectly. I drove around with a Mityvac plugged in to the tranny and no connection with the VAV. With no vac the downshifts were very rough; when I pumped up the vac with the Mityvac, the downshifts smoothed out. But with no vac the upshifts were quite smooth.

I think your post reports actual MB design, but the above is from actual experience. Technically the VAV is designed to reduce the vac as you push the gas pedal; more gas pedal and less vac. So I assume the design would result in medium vac at relatively low speeds and a smooth shift at low speeds. However in my SD the slightest touch on the gas pedal results in an immediate drop to zero vac and I was not able to experience any rough upshift with no vac.

Bowden cable issue. Far too much play after manipulating the linkage. Now 2-3 is a very soft shift, 3-4 is pretty nice, but I have a real 3rd gear again.

Does anyone know exactly what each of of the 2 linkages going over the vale cover does, in terms of adjustment?

You aren't understanding how the transmission works or is designed. With 0 vacuum, the transmission will shift as fast and as hard as it possibly can, ideal for changing gear when under load or accelerating to minimize clutch wear. When shifting with little or no throttle input, this type of shifting is objectionable to the vehicle occupants, so vacuum is applied to the modulator to soften the shift (basically a controlled flare).

The diesel "rube goldberg" setup is designed to somewhat mimic the intake manifold vacuum on a gasoline engine. The vacuum should bleed off with throttle position, it shouldn't simply vanish with a little bit of throttle input. If it does, you have a problem in the vacuum system.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I can't help you with what linkage does what because I'm not familiar with the 617. If you have a cruise control actuator, that may have something to do with one of them.

The 2-3 shift being crappy could be due to the K1 accumulator spring issue. It seems to be an extremely common issue and is super easy to fix next time you service the tranny.

You can fiddle with the bowden cable and tune the shifting to your liking. Tighter (less slack) will cause the gears to hang longer and shift at higher RPM's. Adjust in small increments and drive in various traffic to see how it behaves. With a bit of fiddling, you can dial it in perfect.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I was able to tighten up flaring shifts, especially between 3-4 by adjusting the nut inside the VCV. The VCV bleeds off vacuum depending on throttle position. I did not remove the VCV because I have heard how easily the plastic clip on the linkage can break. You can just pop of the round cover on the side, and while holding the lever and linkage still with pliers, turn the adjusting nut. Just a little bit at a time! I forget which way I turned it, but searching VCV adjustment on this forum will help. Between adjusting the bowden cable and VCV my car is shifting acceptably well for nearly 400,000 miles. Before doing each, I though transmission work was probably on the horizon. My transmission may have been worked on about 250,000 miles ago.

85 300TD, egr, arv, trap oxidizer deleted. 380,000 miles, daily driver

The VCV is supposed to drop vac to 0 at ~10 mm of opening. There is a measurement that can be taken. I glued 2 nickels together and drilled a 1/8" hole to approximate the factory gauge.

There are trans manuals available that have the destructions. I can post a Dropbox link later.

__________________
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.