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Can I use Auto-Rx before change the transmission liquid?

Hi! My Chevy Malibu (1999) has 95,000 miles on it. I plan to change the transmission liquid. A friend told me to pour a can of Auto-RX first, and then let it run 3000 miles to clean the system first before changing the transmission liquid. Does it make sense? Thanks. Lisa

NO!!! I cannot say it any louder or stronger. NO!!!

Do not do this. Auto-RX has some very harsh detergents designed to remove oil sludge from ENGINES, not transmissions. The transmissions don’t build up sludge like the engine. Those harsh detergents will eat away and destroy the internal seals and maybe the clutches within the transmission. A cheap way to spend thousands of dollars to fix.

Just do a pan drop and fluid replacement. Should be the only thing the transmission requires. Hopefully you’ve had this done before. Typical transmission fluid change should happen no more than every 60,000 miles, and some on this board recommend every 30,000, especially for daily commuters and trucks that tow or haul. That’s all I’ve done to mine, between 30,000 and 50,000 miles. I have 226,000 miles on my Ford Explorer original transmission with no signs of any problems.

No, thats not needed. Will probably do more harm than good. just drop the pan, change the filter, check the pan for any debris (Metal shavings, clutch debris) then replace the pan and refill.


If you need a third vote in favor of skipping that additive and going directly to the basic service consider it done. I often recommend some of the tranmission specific additives to use in last ditch efforts to correct problems before making expensive repairs but your transmission just needs preventive maintenance,

When I do a transmission fluid exchange I add a can of Seafoam Transtune to the transmission fluid 500 miles prior to the fluid exchange. This ensures that any gum and varnish in the transmission are disolved and are removed when doing the transmission fluid exchange.

Then afterwards I drop the pan, if possible, and replace the transmission filter, if it has one, and then add transmission fluid to bring it to the proper level.


@tester I put the Seafoam in durring the fluid exchange (instead of 1/2 qt of trans fluid or was it a fill qt… I dont recall now) and left it in… Is this a bad idea? When I first did it the shifts smoothed up and all and all the trans seems to act better…

No. It’s not a bad idea. You can leave any Seafoam product in any system indefinintely and it won’t harm a thing.