Changing automatic transmission fluid

Tiny
MIKEBEENE
  • MEMBER
  • 2011 TOYOTA HIGHLANDER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
My maintenance book does not suggest an interval to change my transmission fluid. I have seen some information that says you never change it.

But I plan to go 300,000 miles in it so it seems likely that some interval is appropriate. There is no dipstick to check the level or be able to see the color of the fluid. Some say when it turns brown, then change it.

Does it matter if it is flushed or drained? I have heard that draining it leaves about half of the old fluid. But I have heard that flushing it can stir up gunk inside and make things worse.

What do you suggest?
Friday, February 23rd, 2018 AT 8:55 AM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning.

Yes, it must be serviced at the interval in your maintenance book. If you do not, then you are going to damage the transmission. All fluids in your car have time intervals to be serviced. Failure to do this will result in failures.

Flushing is not necessary. Just change the oil/filter as suggested. The flushing agent does not react well with the clutches.

Roy
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Saturday, February 24th, 2018 AT 5:54 AM
Tiny
MIKEBEENE
  • MEMBER
  • 3 POSTS
But my maintenance book does not specify an interval or even say it needs changing. So what interval?
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Saturday, February 24th, 2018 AT 8:15 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
There was a TSB about this and it recommends 100,000 for changing the fluid as most manufacturers have this mileage as the time to change.

Roy
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Saturday, February 24th, 2018 AT 8:21 AM
Tiny
MIKEBEENE
  • MEMBER
  • 3 POSTS
Great! Thank you very much! I am overdue, so I wll get on it.
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Saturday, February 24th, 2018 AT 9:22 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Sounds like a plan. By changing it you can feel assured it will last the mileage you want.

Roy
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Saturday, February 24th, 2018 AT 9:40 AM

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