Trans oil change

I have A 1996 Toyota Corolla automatic drive about 6000mi yr I change trans oil 7000mi ago Im told all of old oil can not be changed some still remains in torck converter is there a better way our how often should I change oil P.S. most my driving is in town

I personally change trans fluid at least half of the recommended mileage. For example, if the book reads 60,000 miles, I change at 30,000. Especially if the majority of driving is in-town. Fluid works much harder under those conditions.

And, short of dropping the transmission, most cars have no way to drain the torque converter. A trans flush would replace more, but can be dangerous to some designs, and not worth the risk IMHO.

I would not worry about it. I would likely change it a little more often however, but that is just me. It seems like a good economical move, but really not necessary.

Look at it this way. By the time you drive off the lot, the oil is partly used anyway. If the old stuff was OK last week, the mix should be OK for some time to come.

Never worry about the fluid in the torque converter. If the manufacturer wanted it all chenged, then it would be recommended.

Don’t toyotas have a drain for the TC, my cars do? What’s the point of only changing a portion of the fluid?

The transmission capacity is about 3 quarts (+ or - a half quart, depending on which engine/ A/T is installed). If 1/2 of the old fluid drains out, and you refill, the new mix will be 50% new and 50% old, right? Run the engine, drain and refill that, and the mix will be 25% old, and 75% new. If you ran the engine, drained and refilled that (but, why?), the mix would be 12 1/2% old, and 87 1/2% new, Ad infinitum.