1990 integra automatic transmission 1-2, 2-3

This is an intermittent problem. About half the time it shifts fine. But at other times, the engine revs maybe 500 rpm, before shifting 1-2, and 2-3. Sometimes it’s just the 1-2 shift, sometimes just the 2-3 shift, sometimes both.

I don’t understand how, if the transmission is toast, the problem can occur only sometimes. Anyone have advice? It’s full of fresh fluid. Manual calls for Dextron II. I use the Castrol ATF for Honda. The shop manual says to check the fluid within 1 minute of turning off the engine. I do that, but the method seems inaccurate. 1 minute? 185,000 miles, hatchback.

how did the old fluid look and smell? you should be able to check for transmission codes

What you’re describing sounds like a slip, definitely not a good thing. If it is intermittently slipping, it will get worse sooner or later, its just a matter of time.

i’d be more inclined to look towards the solenoids on an intermittent issue