Transmission of 89 300E

Hi there,
Im just a newbie. I bought an 89 MBenz 300E with auto trans. ( 181,000 plus mileage) last Monday. I noticed that the transmission shifts long ( High RPM) and you can feel everytime it shifts. Do you
think something is wrong with the transmission? My other question, is this a 3 speed Automatic or 4 speed automatic transmission? I researched the internet and its says that this model is a 4 speed Auto Transmission but the car shifted only to third gear.
Thanks.
Boly
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1st gear is engaged by shifting into L at a full stop or by flooring the accelerator at low speed. So one stops, shifts into L - starts off, shifts up to S and immediately back to L to hold 2nd gear, then shifts up to S for 3rd, then to D for 4th.
Your car idles in and starts off in 2nd gear by default; that's so it doesn't creep at idle while waiting for traffic etc. The newer models idle in 2nd but immediately down shift to 1st upon a press of the accelerator.
Shift Quality: The transmission has a vacuum powered shift modulator that's designed to provide soft shifts on light throttle and harsh shifts - no modulation - at full throttle acceleration.
The MORE vacuum at the modulator the SOFTER the shift. So a vacuum leak from a broken or disconnected vacuum line will result in hard shifts. Start at the transmission's right side look for the modulator and a plastic vacuum line attached to it, follow the line up to the engine.
Shift Points: The transmission is "told" the throttle position by a rod, cable or vacuum line - I don't know which your model uses - so the transmission will "know" when to shift appropriately. Take a look at the throttle linkage to see if there's a rod or cable down to the right side of the transmission. If so, come back and I'll tell you how to check its adjustment.
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The mod valve is on the left of the box and is vacuum operated. Check to see if the pipe has come off. Also check to see if there is any ATF in the pipe. The rubber diaphragm can split. If so, then it's a new mod valve.

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Change your fluid and filter to see if the condition improves... but most likely to be the modulator too.
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After reading the posts to the original question I'm wondering if the modulator could be causing the really harsh shifts I get from 3rd to 4th and back under moderate to fast acceleration. Doesn't seem to be a problem under full acceleration.
If the hose were off or the modulator had failed completly would the car not shift at all? Also, I see that it's less than $40 at Autohaus and wonder if it's difficult to replace.
Thanks,
Mike

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