Yes there's 250k on my automatic '99 tranny Accord EX 2.3L. Past month I've noticed tranny may be slow to shift out of 3rd gear on rare occasion. Any idea other than old age what might be causing this. I've noticed at junkyard almost every 6th gen, if its new on yard and tranny hasn't been pulled that solenoid pack on front has been pulled like within hours of being put out in yard.

Is there anything on exterior of tranny I could replace that might be linked to the delayed shifting? I'm not familiar with the different tranny parts so didn't want to just swap out parts and pray.

 

When was the last time the ATF and filter was changed? Clutches and bands and whatnot do wear out over time, but heat is the #1 killer of auto gearboxes and the first thing to cook is the fluid. If it has not been recently changed, do that as well as a new filter and see where your at. Bad shifts could be caused by something like improper fluid pressure which fresh fluid and a clean filter could remedy. You may also want to try a Lucas type additive at that time. With a trans of that mileage, it won't hurt to add some conditioning agents to help with slipping or sluggish shifts. Bad electronics usually cause converter lockup issues, holding or not shifting gears, overdrive not working etc. so I don't really suspect an electronic issue being the cause of your particular issue.