300CD 1978 auto shifts too late

[jsp300D]

Hi, I have a friends 300CD here and the transmission wont shift correctly.

I replaced all the fluid in the transmission and filter and torque converter but, it wont shift correct. shifts very late.

[Gasbeard]

Originally Posted by jsp300D

Hi, I have a friends 300CD here and the transmission wont shift correctly.

I replaced all the fluid in the transmission and filter and torque converter but, it wont shift correct. shifts very late.

Have you tried adjusting the control pressure rod that connects to the throttle linkage?

[barry12345]

A can of transmission treatment? Internal seals could need rejuvenation. Takes about 1000 to 1500 miles to work totally if it will.

[gonesurfing]

If it also shifts hard, I second checking the linkage and pressure control rod adjustment.

[jsp300D]

Originally Posted by Gasbeard

Have you tried adjusting the control pressure rod that connects to the throttle linkage?

Where is this located?

Originally Posted by gonesurfing

If it also shifts hard, I second checking the linkage and pressure control rod adjustment.

Where is this located on the 722.1?

[Gasbeard]

Originally Posted by jsp300D

Where is this located?



Where is this located on the 722.1?

Yes - there's a screw up where the the rod marked in the picture links via ball/socket to the injector pump. Take a flathead, pop the socket off of the ball, loosen the screw, and adjust forward or backward. Very small adjustments make a huge difference.

If you want to go by the book, the factory shop manual has exact procedures. If you want to wing it, adjust slightly, take for a spin to test, park, adjust again, repeat.

Again - easy does it...small adjustments to the length of that rod make big differences in shifting. The transmission linkage is connected to the throttle. When throttle moves forward, it pulls the control pressure rod forward and tells the transmission when to shift. So if it's not calibrated correctly, you'll be applying lots of throttle, with no shifting occurring. Conversely, you'll apply little throttle and it'll shift before there are correct RPMs and you'll lose all your torque.

[Diseasel300]

Seems pretty clearly marked in your picture where the control pressure lever/rod are. Follow it back up to the throttle linkage and see how it's adjusted. Too tight and the shifts will be late and at high RPM.

[jsp300D]

So the control pressure lever which direction does it needs to be adjusted? I have adjusted it now towards the gearbox and it shifts still the same but, need really full throttle to go up to 60mph.

[vwnate1]

? Is this the same set up as my 240D ? .

It doesn't have the bowden cable the later models do .

My 1982D's tranny shifts fine but a little bit too late so the engine is always over revving .

[jsp300D]

So which side to adjust on this rod?

[vwnate1]

At the top end where the ball joint has a long adjusting thread and locknut .

Now all we needs is to know to lengthen or shorten it to make the up shifts sooner .

TIA,

[jsp300D]

Thanks Nate, I adjusted towards the arrow and now it shifts even later. I also need to wot to get to 60mph.

[vwnate1]

Welcome .

Remember : first you need to ensure the lever on the side of the injection pump touches the pump's full limit *just* as the accelerator pedal touches the carpet ~ shouldn't need to mash it hard .

Resist the urge to mindlessly fool with the linkage rods, so many do then everything else goes wonky .

The FSM has the correct initial measurements, two of my W123's had oil soaked and collapsed motor mounts so some dufus adjusted ALL the linkage rods Oh, crap .

The tranny shift linkage is the _last_ thing you touch after everything else has been done and the engine is runniong fine .

Sort of like the carby on an old gasoline engine~ every one fools with the carby first then brings it to me and I have to check and adjust the tight valves, bad wrong setting points, timing 30 degrees off, spark plugs gapped to .024", throttle linkage all screwed up, then I can fool with the TV cable adjustment .

On my post '83 W123's I find 1/2 turn of the bowden cable adjuster (180 degrees) will make a noticeable difference so go slowly here .

[Phillytwotank]

This would be a great time to go over all the rods and linkages. Clean and lube them. Make sure they’re going full travel on the pump side.

[jsp300D]

Thanks nate, All of the rods are already lubricated. Engine runs much better than my own 300D. No smokes at all and no weird noise. It's only the shifting points that is way too late. This car already had an '' italian tuneup'' already