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To change atf or not to

Have 180000 miles on 2000 nissan maxima. The automatic transmission fluid is brown. I am not having any problems (that I know of), and I believe the fluid was NEVER changed. Should I just keep driving it?
Should I drop the pan and clean the pan and filter and replace 4 qts that the pan holds?
Or should I get it flushed out with one of those fancy transmission flushing machines?
The older guy in me says leave it alone it ain’t broke and changing the old fluid might break the tyranny.
the mr fix it in me says change it before it breaks.

I would do a pan drop and change it that way. No flush. This method is the gentlest way to get the change accomplished. I would follow up with another pan drop in 10-15K miles to get more of the older stuff out.

I second jayhawkroy’s recommendation. Not changing ATF fluid is an old wives tales that will not go away. It should but it won’t.

With fluid that old in the system, I would do both. First, I would have the pan dropped and cleaned, and have the filter cleaned or replaced. Then, I would make sure all of the old fluid is out of there by having the system flushed. As Transman will probably tell you when he comments, having the system flushed, without having the pan dropped and cleaned first, can do more harm than good.

I third jayhawkroy’s recommendation but add that you should follow this up with another fluid change in about a 1000 miles and maybe one again after that. Reevaluate at the 10-15k. I fluid is red, OK, if brown, repeat procedure.

I was reading online that the old fluid probably is acting like wet sandpaper giving the “clutches” more grip and if I remove the old fluid I will lose grip. This is an automatic transmission does that comment about the grip make sense?

Bogus, but lets say its true, then I would respond, remove the sandpaper or you will lose your clutches.

“…does that comment about the grip make sense?”

No, it’s bull designed to support an urban legend.

I also read online the 4 new atf quarts have detergents in them and the detergents will dissolve the Sludge from the old atf and destroy/break/cause a problem in the tyranny. Is that also folklore?

Just more old wives’ (or old incompetent mechanics’) tales.
If the fluid change is done properly, the pan will be dropped in order to scrape out the sludge and debris that has accumulated there. Do not go to a shop that wants to solely use a machine exchange of fluids without dropping the pan, as this could actually cause some severe problems on that abused transmission.

In reality, anti-wear, anti-foaming, and anti-friction ingredients in ATF break down over time, and changing the ATF can help the transmission by adding new doses of these additives to the transmission.

However, you need to bear in mind that trans fluid that is now brown, and has never been changed in 10 years, may well be the harbinger of a trans that is on death’s door.
If the transmission fails in the weeks or months following the fluid change, it will not be because of the fluid change. That failure will be because trans maintenance was ignored for 10 years. When fluid is not changed every 3 years/30k miles, trans failure can take place any time after ~100k miles, so yours is actually overdue for failure at this point.

I would change the fluid if I were you, but don’t be surprised if the trans fails anyway, due to lack of maintenance.

Change it and change the filter and add a bottle of Lube-Gard in the “RED” bottle. Your transmission is SEVERLY neglected. I would suggest doing a little better in keeping it serviced. (Every 25-30k miles)


“…does that comment about the grip make sense?”

If true then that sandpaper is also wearing at the bearings, gears, hydraulic pistons, seals etc.

Not good.


I dropped the pan and changed the fluid 4.5 qts and added the lube guard.
the pan had metal “flakes” and the filter was like new.
Old fluid was dark and now mixed fluid is pinkish color.
Tranny seems to run smoother.

How many miles should I wait to change the rest of the bad fluid(6 out of 10 qts)?
When i change the fluid should I drop pan and check filter again?

Once you drive it just a few miles the fluid has circulated…If it’s that bad then I’d change it out in a day or so.

This time I would go with a flush, and I wouldn’t wait to do it, especially since you saw metal flakes. This will help you make sure you get 100% of the old fluid (and 100% of the metal flakes) out of there.

The only place I saw the flakes was on the magnet. The fluid was dirty but flake free and the. Filter was flake free too

I can say that I have ever drained a transmission and didn’t see some metal flakes in the oil. I would change it again as soon as practical.

“The only place I saw the flakes was on the magnet. The fluid was dirty but flake free and the. Filter was flake free too”

In that case, just do a drain and refill with the drain plug, as long as you don’t think there are still metal fragments in the fluid, that should be fine. I still don’t think there is any reason to wait though.

What did the metal look like?? Did it look like aluminum, brass, or steel shavings?? Was there a lot of shavings??