Transmission Fluid Replacement

I read this somewhere and I wanted to see if this is a load of sh** or it could actually be true. “If your vehicle has high

mileage (> 80,000 miles) and regular transmission servicing has not been maintained, I would not recommend replacing the fluid and filter. The fluid that has been in the transmission has become dirty and gritty.

This gritty fluid acts like

liquid sandpaper and provides needed friction for the worn internal parts. Changing the fluid and replacing the filter removes this friction. Clutches can slip on new slick fluid. You might actually be doing more harm than good.”

If I can surmise from past posts on the issue it seemed to me that a trans flush is good, and if it toasts your transmission you had imminent repairs anyway.

This question has been discussed in detail on this board, and I think the consensus is that the recommendation and rationale to not change is wrong. Nearly all of us here recommend fluid and filter replacement every 30 K miles or so. If you happened to miss the mark initially is no reason to not replenish the ATF with new, good fluid.

If something goes wrong and kills the transmission, it is because the transmission was most likely terminal, anyway.

I missed the flush part in your key words. A pan drop, filter change, and new fluid could work nearly as well as a full fluid replacement. Also, check your owner’s manual. At one time, Honda recommended two or three successive drains and fills to replenish the fluid, and no flush.

Sounds like oats that passed through the bull. There is nothing better for a car than regular maintenance, better late than never. Take it to a shop that you trust and have them change the fluid and filter to remove the grit that may be chewing up the insides of your tranny.

30k? check your manual for specifics. 100k for me.

My 2001 Mazda manual said nothing about trans fluid changes at all, but I know what the fluid was like at 65K. I would personally recommend changing much sooner,and do in all my cars.

This is one area where I do not follow the owner’s manual if the ATF recommendation is longer than 30K. No manufacturer is going to admit guilt at being wrong on trans service at 100+K. Transmission repair is an area where I am very conservative in my maintenance view.

“30k? check your manual for specifics. 100k for me.”

Right, but people who actually rebuild transmissions will give you 30K regardless of what the manual says. I’m sure that’s not completely unanimous, but it is the general word.

To the OP - its important to have the pan come off to inspect its contents and to get a new filter in there. Do not just have someone “flush” it. And you should just do it. If the trans is so far gone that it needs this “grit” to make it work (even if that makes sense) then it is gone anyway.

It’s an old wives tale. Change your fluid and replace the filter to extend the life of your transmission.