ok ive been reading on here for a long time and have done some of the vacuum testing. my trans only flares on the 2-3 upshift other than that its fine. it seems to shift fine at full throttle only flares under light to moderate shifts. my modulator is holding vacuum, plugged the egr, my vcv has about 13" at idle 0 at full throttle. what would my next step be?

do a search on K2 spring replacement --- I think there is a DIY article. I have it on my list of things to do to Coda.

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
No longer selling Cluster Needles Paint
No longer selling New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

13" a bit high for idle.

I'd make a small adjustment to the vacuum amplifier (blue flying saucer). Remove it and you'll find a black plastic cap on the bottom. Remove the cap and you'll find a plastic hex screw..........4mm IIRC. Turn the plastic hex screw clockwise by two turns and reinstall the amplifier in the vehicle.

Reconnect it and take it for a drive. See if the flare is gone.

it shifts like a champ now. thanks. i cant believe the amount of knowledge on this site. ispent hours reading on how this trans works and still couldnt fix it thats awesome thanks again!

Excellent.

Help is what we do here.

I am experiencing exactly what your syptoms were. I saw that there were a couple of suggestions as to what to adjust or replace to fix this...(flying saucer and K spring) which was the solution to the problem?

Thanks alot

James

1993 300CE

You've got a gasser...........must post over in Tech help for assistance with that.

Hey Brian:

I've got a somewhat different problem. The tranny downshifts with a noticeable clunk when coming to a stop. If I drive with the shifter in third gear, it does not do this. Only if in drive, so I think it must be that last gear that is coming down hard.

Is there any adjustment to be made for something like that?

Edit: for a 91 350SDL

Hmmmm.....something for me to try before I replace the spring. THANKS, Brian!!!

__________________
daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
No longer selling Cluster Needles Paint
No longer selling New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

I was considering replacing the 123 unit... I didn't know it was adjustable...

-Jason

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

What's a "123 unit"?

Which vehicle?

What issues?

The blue and white saucer, in all the vacuum diagrams it's always number 123, and mine has 123 printed on it, even though it's part number starts with 126.

On my 350SDL shifts are always too firm, even after adjusting the modulator on the injection pump. Unplug the boost line going to the 123 unit and then shifts are way too soft.

-J

It's called a "vacuum transducer" or "vacuum amplifier"........your choice.

There is no "modulator" on the injection pump. The IP has the vacuum control valve (VCV) attached to it.

Get a reading of the vacuum at idle from the VCV output to the amplifier. Get another reading at idle from the amplifier to the modulator (transmission).

My suspicion is that you've got a vacuum leak.

EPCnet Online the official Mercedes-Benz USA, LLC site for hosting spare parts documentation for Mercedes-Benz cars and light trucks sold in the USA seems to designate it as the "PRESSURE CONVERTER". Item no. 941 Part number
A 123 300 11 33. In case someone is getting blank stares at the parts counter.

One wonders if a retrofit of this item on pre '85 diesels is doable and worth the trouble.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

My 1992 300D sometimes flares between 2 and 3 shifts, does my 300D have this adjustment also?