S124 722.4 gearbox issue
 

Hello,

I have a problem with my 722.4 gearbox, when the car is cold and i put it into gear the car has a difficult time to start moving, the whole car shakes and feels like it's slipping, it doesn't occur when i'm driving downhill or the engine is fully warm. I have changed the B2 piston push rod for a longer one, replaced the K1 and K2 springs, the B2 piston teflon ring and the filter about a year ago, i have also replaced the front and rear flexdiscs. The fluid is on the correct level. Once the car gets going it drives and shifts really smooth. It only has this problem when it's cold outside, there was no problem during summer.
What could be the issue?

Have you tried turning up the modulator pressure?

A set of gauges to see what working pressures at the front pump and the valve body would be Very helpful...


What fluid are you running?


Jono

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I haven't tried turning up the modulator pressure, im running XL ATF DEXRON II-D.

Give it 2 full turns (6 lbs more pressure).

Good fluid, so we'll stick with that for the time being:)

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These 722.3's/722.4's suffer from cooked parts.

While changing B2 "dog bone" from a smaller one to a larger one did you change the B2 black piston seal, and did you note how ripples were on the shaft of B2 piston?

Now you could have cooked B1 and B2 brake bands as the skipping you are feeling(when cold) the contracting of B1 and B2 because they burned-up, and just cannot grip the clutch pack drums.

Martin

If it's over 100K miles you are probably looking at a toasted trans. Take out the filter and pry it open with a pair of pliers. The edges of the filter are crimped over and can easily be pried up. If you find what looks like bits of a gasket in there, it's your second gear band friction lining and you are looking at a rebuild. Highly recommend Sun Valley.

If the transmission was utterly burnt warm fluid wouldn't fix it.



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i gave the modulator 2 turns and it got alot better, it still does this when trying to drive uphill with a cold engine, but since we don't have that many hills in estonia, i think i'll be fine :D thank you for the help!

If two turns improved things go 2 more.

Also, since it Did respond so well I'd drain the pan and re-fill with type F fluid. It will give your clutches and bands a new lease of life....F is lacking a lot of the friction modifiers that DM II/III has.

Been running it in All my personal cars now for going on 10 years...as well as any performance builds OR tired transmissions. Saved people $$$$$$ with modulator pressure and Type F;)

Jono

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