My 89 260E has been getting progressively worse gas mileage. I suspected the transmission may not be shifting correctly. I had the ATF and filter changed a couple days ago. The filter was clogged. There was no debris in the fluid. Seems to be better. My question is how many times should it shift? Accelerating slowly, it shifts at ~20mph around 2000 rpm or even a little less. It shifts again at 25 or so mph at the same rpm. It doesn't shift again. RPM at 65mph is a little over 3000rpm. The gear selector has 2,3, D, so it would seem two shifts are correct, but I drove another car with the same shift numbers on the selector, but it shifted 3 times. That car was a little newer 300CE, so maybe a different transmission.
I have read other posts regarding using something that may help rid build-ups and then replace with synthetic ATF. Is this something to do with a high mileage transmission?
Many thanks to all. I have been read this site for some time and only decided to register today to ask this question. (And I have a couple more.)

pre late-91 cars start in 2nd, so that's why you only feel 2 shifts. My car is a late '91 and it starts in 1st. Mine used to shift around the rpm you describe, but I adjusted it to shift higher (around 2500rpm) for better acceleration, though slightly harder shifts.

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1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
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"music and women I cannot but give way to, whatever my business" -Pepys

The car's speedometer shows how many shift points the car has with the dots ont the dial face.

One other factor that may affect shifting is the Bowden cable, which has adjustments at the throttle cable.

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95 E320 Cabriolet, 169K

Thank you both. My speedometer has one dot at 50km/h, two at 90km/h, and three at 145km/h. That would not be normal shift points, would they? Or would it be maximum speeds when acclerating hard?
The car I drove that starts in first gear was a 92, I think. But wasn't a 91 or older.
Where can I find out which transmission I do have? (I see numbers in some posts.) Is there a place the MB has that gives specs.
I also was told by someone the RPM should be half the speed. (ignoring some decimal places.) ex. 60mph is about 3000rpm.
Now I have to find out how to adjust the cable you suggest.
Thansk again.

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John
89 260E 236,000 miles
97 E420 106,000 miles
87 Volvo 765 312,000 miles
07 Volvo S40 T5

The dots on the speedo show the safe speed ranges for each gear (up to the first dot for 1st gear and so on).
The bowden cable is easy to adjust, it is located under the air cleaner above the oil filter.
Do a search and you should find plenty of posts on how to adjust it.
My car is a '92 model, but was made late '91, when they switched to the 1st gear start.

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1993 320TE M104
---------------------------------------------------
past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
----------------------------------------------
"music and women I cannot but give way to, whatever my business" -Pepys

Thanks again for your time. I'll look up how to adjust the cable. I see your car for sale. Good luck in the UK.

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John
89 260E 236,000 miles
97 E420 106,000 miles
87 Volvo 765 312,000 miles
07 Volvo S40 T5