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1981 300D with a funny tranny
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Discussion Starter #1 (Edited)
Hello,

I though that I should put together in a simple manner all I found out in the process to fix my flaring tranny. I hope this information is useful.

Please add more details, pictures, videos, etc


Its kinda pointless to mess with the tranny if the engine is not working properly. Although, usually the problems come from vacuum leaks. Assuming your engine is running Ok, then just go hunt for vacuum gremlins.


Engine:

-ATF level. If its leaking click here.

-Change all Filters.

-Fuel hose leaks. Upgrade Hand primer pump for a new bosch.

-Chech tank screen.

-Valve Adjustment. Check the Timing chain.

-Compression Test.

-Clean Injection System with Diesel Purge. And Or upgrade to Monarch Nozzles.

-Timing, Injection Pump

- In the case of a Turbo diesel, check your turbo for proper functionality and clean it. Use the ALDA screw to adjust for a richer air mix. Clean the "banjo" bolt.

-Oil consumption/loss.

-Linkages, are they working right? moving smoothly?

-Glow plugs, if the engine is starting rough/ smoking and gets better at Op.Temp. When changing them you may want to get rid of the carbon buid up using a "reamer":
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1594582-replaced-glow-plugs-carbon-reamer-clean.html

-Tranny additives... this is what Benzworld think:
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1550717-tranny-additive-good-bad.html


=============================================



Vacuum:


- Simplify the vacuum routing. Delete EGR. Leave one of the vac lines from the main hose going directly to the VCV with a "Y" connector shared with the black line that goes directly to the Modulator. Connect your MV to "other users" one by one to test for leaks again. Then start connecting one by one "other users" to see if there is a leak in one of such systems. Go for a test ride with each one of them. Usually there is a leak in the Door Locks or Climate Control, if that's the case, bypass it and deal with that later. EGR is not needed, you should bypass it.


- Replace all rubber connectors that look aged or brittle ... Its cheap, just do it all. Don't forget the most important one at the Modulator.

- Check Modulator vacuum line is holding pressure. Usually black, goes from the top of VCV to under the car and connects into the Modulator. If not, replace the line and go to the modulator itself and check if it holds vacuum .

QUOTE: "You don't necessarily need to replace the modulator if it doesn't hold vacuum. Sometimes you can replace the rubber O ring or rubber cap to repair it. Only if you draw oil through it, you'll need to replace the modulator."-GOVERT70227

If the modulator doesn't hold vac, the you may need to replace it. Although is not just swapping parts it needs to be adjusted to the right pressure and the new piece doesn't come with a thrust pin, look inside of the old one and use that part with the new one.

- Check main vacuum hose and Pump (It should read 21-25 inches of Hg). Disconnect main vac hose from brake booster and plug that end with thumb, connect mighty vac to both plastic tees (with a Y connector) that were connected to all vacuum lines. Use the MV as a gauge. This is done with engine at idle.

-Disconnect Cruise control electric plug and then disconnect all vacuum hoses but one going in top of the VCV and tho other to the shut off valve. You are leaving out cruise control, climate control, EGR and door locks.

-VCV adjustment, this is a valve that leaks vacuum in relation with the position of throttle. Its located in top of the IP and is made of a white/yellowish plastic. It can be adjusted to control when shifting happens, this is usually THE FIX. With old/worn trannys, you may have to deal with a harsh 1-2 shift to avoid flares between 2-3 and early 4th gear. Use your MV as a gauge between "Y" in top of VCV and Modulator line, original set up is 15Hg at idle to 0Hg at full throttle.

Check this link by Gregs300CD: http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1261744-transmission-flaring-clunking-vcv-diy.html


Remember that you need a check valve at least closing the door system and reservoir.

-Someone messed with the Mod. pressure before... well, that's a tough one... regulating the Mod to specs is a real pain in the ass. But it can be done with a gauge connected to the test port, sometimes can only be read with the car running at 50mph.


=================================================

Simple Explanation of 722.xxx Mercedes Trannys:

-Hydraulic pressure controls Shifting.

-Hydraulic pressure is set by the primary pump and governor. This is NOT adjustable.

-Some pressure can be adjusted externally to control timing and quality.

-4 types of pressure work in concert:

a. Working Pressure: From the front driven primary pump, and its the basis of all pressures. Cannot be adjusted, but can be measured by a port.

b. Governor Pressure: Builds pressure with centrifugal force in a gradual proportion as the speed of the tranny increases. It works directly against control pressure to regulate the shift depending on vehicle speed. Cannot be adjusted, but can be measured by a port with the car driven a certain speeds.

c. Modulating Pressure: controls the working pressure, from partial to full throttle. Modulator can be adjusted to harden or soften the spring inside it. One way is constant, by turning the key inside it and the other way is constantly changing because is vacuum. This vacuum is also controlled by the VCV which leaks vacuum in proportion of the throttle position. Modulating pressure controls the shifts by varying the applied pressure to the bands on the clutches. Modulating pressure acts as a control for the working pressure in proportion to the torque of the engine. Can be adjusted by turning the key in the modulator and checking the pressure in the port close to it.

d. Control pressure: This is relative to the pedal position. Obtained from the modulator by means of the control pressure valve, which is influenced by the linkage or cable from the tranny to the accelerator linkage.




Useful Diagrams:

Vacuum:


Engine 617.912 (Model 300D/CD/TD) [1980 federal?]


Engine 617.950 (300SD)


1980 CA


1981-1984


1984-1985


1985 CA






---------------------------------------------

1981 300TD non-turbo


QUOTE: "Valve 64 is for the transmission, valves 64a en 64b are for the EGR (EGR shut-off for idle and full load).

Valve 64 switches between full vacuum from the pump (nr. 1 on the plug) at idle and Controlled Vacuum from the VCV. It does that by connecting 1 and 4 at the plug at idle and connecting 4 and 5 when the accelerator pedal is pressed.

In the picture it seems like 1, 2 and 3 are connected and it also seems as if not all the switchover valves are there, but the picture is not clear.

If you want to by-pass the EGR, simply plug nr. 3 port. That works if the switchover valves are still working and not leaking. I'm not sure if the switchover valve 64 is dependent on either 64a or 64b, but if not, you can remove 64a and 64b or plug them.

You can also repair the switchover valves, sometimes a rubber line or a little flipper is worn out.

Alternatively you can install a simpler 1980 switchover valve or remove the switchover valve altogether as was originally suggested. The transmission might not shift back to first upon take-off or stand in first in idle (so that it pulls harder), but I suppose you could live with that. " -by Govert70227

------------------------

WEBSITE WITH VACUUM DIAGRAMS, CLICK HERE







Shifting points for NON VACUUM PRE-1980:







Linkage:






VACUUM EGR DELETE (Rmac58) :


above, the blue painted line goes thru the firewall to leak, its open an usually black

Useful Links:



PROPER VACUUM SYSTEM "TUNING" ACHIEVES OPTIMAL SHIFT CHARACTERISTICS AND AN ACCURATE REPAIR



DIESEL PURGE



VALVE ADJUSTMENT



INJECTOR NOZZLE REPLACEMENT


EGR DELETE BYPASSING MAINFOLD

VACUUM TROUBLESHOOTING BASICS

Mercedes 123 126 Diesel Transmission Ultimate Diagnostic and Tuning Kit


Helpful thread: "Transmission Experts: Please help"



PEACHPARTS THREADS ON THE SUBJECT by Whunter


Video from mercedes source about shifting problems:





Thanks to all the people that helped me with advice and images, you guys rock!!
 

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2001 Volvo V40
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You don't necessarely need to replace the modulator if it doesn't hold vacuum. Sometimes you can replace the rubber O ring or rubber cap to repair it. Only if you draw oil through it, you'll need to replace the modulator.

The thrust pin needs to be glued into the modulator.

Also the shift point table is for non-vacuum transmissions, pre-1980.
 

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1981 300D with a funny tranny
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965 Posts
Discussion Starter #3
You don't necessarely need to replace the modulator if it doesn't hold vacuum. Sometimes you can replace the rubber O ring or rubber cap to repair it. Only if you draw oil through it, you'll need to replace the modulator.

The thrust pin needs to be glued into the modulator.

Also the shift point table is for non-vacuum transmissions, pre-1980.
its good to know that could be just the oring!:thumbsup:

Do you have the right table?
 

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1981 300D with a funny tranny
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965 Posts
Discussion Starter #4
Transmission DIY links collected by Whunter from Peachparts :


Bad trans = overheating engine

Vacuum diagrams w123/126

Transmission pan drain plug lbs torque


722.xxx transmission rebuild or valve body cleaning; mystery pin


Mercedes 300SD Backup Lights



info on 722.3 - 722.5 transmissions


722.1xx help in W116 needed



Quick Torque Converter Question + general transmission data


transmission bolt/nut torque figures


How abnormal is this trans fluid color? 722.6


'65 190D column-shift linkage puzzle


Vacuum Modulator links thread


transmission slipping need expert advice please



MERCEDES-BENZ TRANSMISSION VACUUM CONTROL SYSTEM "TUNING"
by Steve Brotherton First Published in: ImportCar Feb 2002


Transmission shifting response & “vacuum span” (Stevebfl, are you out there?)


It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...


Vacuum Control Valve


Bad Vac Control Valve?


whining noise from rear that increases with vehicle speed, not RPM



Rear diff fluid ???


differential fluid change


I broke the K1 repair kit!!! What did I do wrong?



K1 Spring Kit



another K1 thread


Run, don't walk, to the dealer, get a K1 kit!!!



replacing B1 piston


B2 Piston Failure



722.118 transmission B2 servo/piston *B2 Piston*


I Am Really Hurt Now *B2 Piston*


C220 won't go forward. HELP!!! *B2 Piston*


B2 Piston W124


My Superior Shift Kit thread (W124 300DT)


car won't reverse!!!!!!!!!! HELP!!!!!!!!! *B3 piston*



No Reverse! Transmission rebuild help. 722.354



722.6 Transmission Fluid Change with pictures


1983 300SD transmission mount Good/Bad pictures


Bad Flex Disc


U Joint ? "center driveshaft bearing"


92 300D 2.5 flex discs,diff. mounts and damper



[URL="http://www.peachparts.com/shopforum/showthread.php?t=54776"]Bowden cable, is this the adjustment



Bowden Cable



Broken Neutral Safety Switch and replacing shifter bushings



Replacing all shifter bushings on W126 - p.1



240D kickdown switch and throttle adjustment



No kick down on 240d auto tranny


kickdown switch adjust on 240D


1982 300SD output flange splines & retaining nut are damaged 722.303 trans


dealers are useless for manual shifter parts......need VIN



Manual Trans. Service/Adjustment Manual???


AUTO TRANS DIAGNOSIS - 722 SERIES, Article Text, 1996 Mercedes-Benz C220


1984 300D Trans Rear Main Seal, anything else?


722.0, 722.1 and 722.2


and for the 722.3 and 722.4


MB Automatic Transmission Overhaul Manual, some come with a DVD

and: European Import Transmission Manuals


Mercedes-Benz 722.3 / 722.4 Automatic Transmission ATSG Rebuild Manual - Softcover
 

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2001 Volvo V40
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2,953 Posts
Here are the shift points for the 722.1, 722.3 and 722.4 (1985 Cali models) transmission from the German FSM. Leergas is light throttle, Vollgas is accelerator pedal fully pressed, but not kickdown. Übergas is kickdown (Übergas sounds much better IMO).

Remember that the speeds are in km/h, not in mph. Also MB mentions that the speeds are approximate, differences in the speedometer, transmission, tyres etc. can mean that the actual shift speed differs from the theoretical shift speeds.

Shift speeds can be used to determine whether the bowden cable or shift rod is adjusted properly. On vacuum-only models it can be used to check the vacuum system: too much vacuum means early shifts; late shifts means not enough vacuum.

The 722.1 transmission shifts earlier on the USA models as you can see:









Switchover valve(s), a.k.a. 3/2 valves

The Switchover valve or valves on top of the valve cover are used for the EGR only on the turbodiesel models, so the switchover valve can be removed without affecting the engine or the transmission (as long as you don't create a vacuum leak upon removal).
On the non-turbo models the switchover valve or valves are used too for the standing in second gear and the shift back to first gear on take-off. If you remove the switchover valve, the transmission might not work as it is supposed to.

The FSM has excellent diagrams for the vacuum setup. They differ from year to year. It can be found in section 14.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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6,561 Posts
Here are the shift points for the 722.1, 722.3 and 722.4 (1985 Cali models) transmission from the German FSM. Leergas is light throttle, Vollgas is accelerator pedal fully pressed, but not kickdown. Übergas is kickdown (Übergas sounds much better IMO).
...
Have you got this type of information for the diesel engined transmissions such as the 722.118, 722.120 or 722.303?
 

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Have you got this type of information for the diesel engined transmissions such as the 722.118, 722.120 or 722.303?
Yes, some of the tables are of the above-mentioned transmissions. The FSM has all the information. First establish which main type transmission you have (722.1, 722.3 or 722.4), than look in the table at the car type (e.g. 123.133 = 300 D Turbo).
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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Yes, some of the tables are of the above-mentioned transmissions. The FSM has all the information. First establish which main type transmission you have (722.1, 722.3 or 722.4), than look in the table at the car type (e.g. 123.133 = 300 D Turbo).
Thanks

Sorry I was being thick. I didn't think of backwards tracing via chassis number

For my 123.130 I need this image



EDIT:-

Do you happen to have a paper German FSM or a German version on CD?

The English translations on the CD don't have a chapter for the transmission you see...
 

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Thanks

Sorry I was being thick. I didn't think of backwards tracing via chassis number

For my 123.130 I need this image



EDIT:-

Do you happen to have a paper German FSM or a German version on CD?

The English translations on the CD don't have a chapter for the transmission you see...
That is only applicable to the 123.130 if it is an USA model before 1980.

I have a FSM in German.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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That is only applicable to the 123.130 if it is an USA model before 1980.

I have a FSM in German.
So you think the 123.130 data will be different for a car that was originally sold in Switzerland?

I see from adverts on Marktplaats that the German FSM CD has a chapter on the automatic transmission whereas the English version does not... now do I fund someone's CD copying business or not?
 

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2001 Volvo V40
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2,953 Posts
So you think the 123.130 data will be different for a car that was originally sold in Switzerland?

I see from adverts on Marktplaats that the German FSM CD has a chapter on the automatic transmission whereas the English version does not... now do I fund someone's CD copying business or not?
Quite different, because the 1981 300D has vacuum control. See the first table for the 722.1 transmission.

You can always buy the DVD from Mercedes-Benz, if you want to fund MB's copying business:

W123DVD

Helaas kan ik je geen pm versturen.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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Right OK so in "real terms" do you happen to know what sort of transmission was fitted to the US 123.130 then?

My 1981 123.130 has a 722.118

Was the US one a 722.120 for example?

From what you are saying it sounds like that whatever was fitted, it did have the more common regulating pressure control lever coming out on the front right hand side of the transmission (which is then connected to the throttle linkage)

(Ik snap niet wat het probleem is met de pm systeem - er zijn slechts twee pm's in mijn inbox - zal ik je een pm als test steuren?)
 

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The USA 123.130 also had the 722.118 transmission, but it was adjusted differently from the Euro models. Australia, Japan, Sweden and South Africa also had differently adjusted transmissions. The result is a transmission which shifts earlier. Perhaps done to increase the mileage figures.

The control rod is the same for USA and Euro models.

The 722.120 transmission is for turbodiesels.

Bij de opties heb je het toelaten van PM niet aangevinkt, daarom kan ik je geen pm versturen.
 

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The USA 123.130 also had the 722.118 transmission, but it was adjusted differently from the Euro models. Australia, Japan, Sweden and South Africa also had differently adjusted transmissions. The result is a transmission which shifts earlier. Perhaps done to increase the mileage figures.

The control rod is the same for USA and Euro models.

The 722.120 transmission is for turbodiesels.

Bij de opties heb je het toelaten van PM niet aangevinkt, daarom kan ik je geen pm versturen.
Some of the 123.130 models appear to have had a transmission with a control rod that can't have been a 722.118 because that doesn't have this feature - I know that because I've got one! I'd like to know which transmission was used instead.

PM messaging has been enabled - far too many options for my simple brain!
 

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Discussion Starter #18 (Edited)
Some of the 123.130 models appear to have had a transmission with a control rod that can't have been a 722.118 because that doesn't have this feature - I know that because I've got one! I'd like to know which transmission was used instead.

PM messaging has been enabled - far too many options for my simple brain!
Army, do you mind sharing your symptoms?

It may be as easy as a tired VCV , meaning the tightening of a nut.

1980s 722.118 regulates quality and timing of shifting by vacuum only. Assuming that your modulator is set to the right pressure.

I have a 722.118, and I'm happy to be able to adjust the VCV only.
 

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Army, do you mind sharing your symptoms?

It may be as easy as a tired VCV , meaning the tightening of a nut.

1980s 722.118 regulates quality and timing of shifting by vacuum only. Assuming that your modulator is set to the right pressure.

I have a 722.118, and I'm happy to be able to adjust the VCV only.
Thanks for the reply.

At the moment I have no symptoms!

I've just rebuilt my transmission and the engine and the... and the... and the whole car... and I'm still busy welding and painting etc etc etc etc etc - blah blah blah...

All I'm trying to do is to gather as much information as possible for the scariest bit of my transmission rebuild => setting it up and adjusting it.

You've done a great job for me so far - so thank you very much!

However, as you say in post #1 starting from scratch is a bit of a problem.

I get the impression that the 722.118 which has no regulating pressure linkage connection to the throttle is a particularly awkward beast to adjust... mainly because there is little information available.

I've got the ATSG manual but most of it is geared towards (pun intended!) the other more plentiful with-a-regulating-pressure-connection-to-the-throttle type transmissions.

I plan to get hold of a German copy of the FSM as that at least has a chapter dedicated to transmissions.
 

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Discussion Starter #20
I get the impression that the 722.118 which has no regulating pressure linkage connection to the throttle is a particularly awkward beast to adjust... mainly because there is little information available.
Well, "theoretically" is the least complicated. You will be in the best position to argue that.

Simple Explanation of 722.xxx Mercedes Trannys:

-Hydraulic pressure controls Shifting.

-Hydraulic pressure is set by the primary pump and governor. This is NOT adjustable.

-Some pressure can be adjusted externally to control timing and quality.

-4 types of pressure work in concert:

a. Working Pressure: From the front driven primary pump, and its the basis of all pressures. Cannot be adjusted, but can be measured by a port.

b. Governor Pressure: Builds pressure with centrifugal force in a gradual proportion as the speed of the tranny increases. It works directly against control pressure to regulate the shift depending on vehicle speed. Cannot be adjusted, but can be measured by a port with the car driven a certain speeds.

c. Modulating Pressure: controls the working pressure, from partial to full throttle. Modulator can be adjusted to harden or soften the spring inside it. One way is constant, by turning the key inside it and the other way is constantly changing because is vacuum. This vacuum is also controlled by the VCV which leaks vacuum in proportion of the throttle position. Modulating pressure controls the shifts by varying the applied pressure to the bands on the clutches. Modulating pressure acts as a control for the working pressure in proportion to the torque of the engine. Can be adjusted by turning the key in the modulator and checking the pressure in the port close to it.



d. Control pressure: This is relative to the pedal position. Obtained from the modulator by means of the control pressure valve, which is influenced by the linkage or cable from the tranny to the accelerator linkage.


About "4 bolts pan" 722.118:

..."In 1980 the transmissions mounted behind non -turbo engines were given a makeover. The 722.118 transmission was only delivered in non -turbo models up to 1983. They are unique in the way they shift. A vacuum modulator was added and the old pressure control rod removed. No means of externally adjusting control pressure was provided. This meant vacuum was used to control both the timing and quality if the shift. Only modulating pressure could be adjusted and in this transmissions it meant modulating pressure had even more direct effect in control pressure. Along with the modulator, an EGR valve was also added to the intake mainfold. Either one or two 3/2 switchover valves were mounted on the valve cover with fairly simple vacuum routing to control the EGR and to help bleed off vacuum at the VCV. Something else showed up on these models. A small color coded restriction orifice embedded to the vacuum line going to the VCV."...

Modulator located RH rear of the case.

Test port is below to the right. 4 o'clock. Should read 2.8 bar or little less than 42psi. Use a banjo bolt (with 2 aluminum washers like the one already in the port) connected to a 0-200 psi gauge. May have to drive at 50mph to read.

I hope this info is accurate and it helps when the time comes.
:D
 
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