...............when I am checking transmission fluid. I drove car for like 20 minutes parked on level ground shifted thru all gears, oppened hood pulled tranny dipstick wiped it then reinserted it back in. What should be my reading. I have reading of 90 on dipstick and that is where the fluid is at. Where should fluid read after 20 minutes of driving on dipstick thank you.
The car is 1993 Mercedes 300D 2.5 TURBO.

Should be the same. You should check the fluid with the transmission hot, with the engine running and the trans in P or N. Checking the level with the engine off will not give an accurate reading, and the fluid expands some as it warms up.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Yes I did have the engine running. When the engine is cold from staying overnight and not running I have more fluid in tranny then when the tranny is hot so I guess fluid shrinks when the car is running instead of expanding. I hate my car because everything is in euro metrics (temperature gauge is in celzius, outside temperature display is in celzius, no power seats, even my tranny dipstick reads in celzius and I have to convert everything into farenheit ).

Cold/Not running - you have more fluid because overnight it has drained down into the pan.

Hot/running - the fluid has been pumped up into the trans valve body pressuring the system and making you mistakenly believe there is less. Hot the fluid expands greately.

No diff than engine oil, it is designed to be checked hot.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

How much does the volume of ATF increase per degree of temp change?

Depending on model, enough for an 8-12mm rise in dipstick reading.

Sixto
87 300D