Old car a/t oil

Many times you would remove the ATF fluid by removing the hose to the radiator and running the car at idle to purge out the ATF. You can slowly pour fresh ATF in while it is running to flush out the nasties. Drop the pan and change the filter. Replace the seals and fill with new fluid.

Can't see why you couldn't change it. The car won't run without it and it couldn't hurt. Thats like using your old oil an additional 5,000 miles cause you missed the scheduled oil change.

Sir I appreciate your time to answer my question. Twice the comments came from Western Auto mechanics; the first time was in a TV show, I heard the same story several times before usually the sources were auto mechanics.

Sir, they specifically refer to transmissions where the oil was not replaced for years. Not from transmissions that where the oil was periodically replaced since new. Do you think it should be no problem under both circumstances?

Hello guest, I'm just curious what they expect you to do if you can't replace the losted transmission fluid. I agree with a previous post. Additionally it might not be a bad idea to drive the car a couple of weeks after you make repairs and refill the transmission, then change the transmission fluid and install a new filter. If any material is dislodged, or you've shaved a little material off the clutch packs by the transmission slipping due to being low on fluid you can remove it at that time.

If the clutches in your transmission are worn too thin, nothing you do is going to put new facing material on those clutch plates.

The clutches in an automatic transmission are applied by aluminum pistons with thin rubber lip seals. If these seals wear too much, they may not reseal after they are allowed to have air behind them. This could happen when changing fluid in the transmission.

Another problem is the oil pump in the transmission. If it is well worn, it might not re-prime itself after an oil change.

There is a way to deal with both of these problems if they should happen.

In the case of the piston seals not sealing, and allowing the fluid to pass around the seal, and not force the piston to lock up the clutch. Raise the viscosity of the fluid to make it harder for the fluid to force past the seals. Once there is sufficient pressure to force the seal against the sealing surface of the cylinder the piston rides in, the clutch will apply.

In the case of a transmission oil pump loosing it's prime, just overfill the fluid till the pump is flooded, and it will pump again. Adding viscosity booster will speed the process.

In many tears of earning a living from vehicle maintenance, The above only happened once. And that was on a high mileage truck that was drained overnight. Two cans of STP oil treatment returned it to service again.

If I was earning a living repairing automatic transmissions only, I would tell everyone that would listen that draining transmission that has not been changed regularly will cause the transmission to fail.

If you still want to put old transmission fluid back in, I do have a limited supply of used transmission fluid from other people that refused to change their transmission fluid and burned up their transmissions. It is priced at only $6.75 per quart, plus shipping and handling. There is a limit of 55 gallons, so act NOW.

Very good answer,good explanation,thank you for your time.

Today I was looking at a Lucas product designed to clean the transmission fluid, and seal leaks and thicken the fluid.

Thank you again,I will check that Lucas product.