Transmission

96 4runner 205k miles. My trans fluid is a little on the darker side and a transmission tech in my town told me with it being at 205k changing the fluid would ruin the transmission and that if it’s not leaking let it be. the Toyota dealership said other wise. I’d like to know it has clean fluid inside of it but I’m also worried the tech wasn’t wrong

 

Transmission techs hate changing fluid on high mileage transmissions because:

1. All automatic transmissions have a certain life. High mileage ones are nearing their end.
2. The owner will be pissed and blame them when it fails.

The thing is, new fluid is definitely going help. It's going to add some lubrication and reduce friction in the system.

My car had 250k miles before I changed out the fluid. It was black as used oil. No shavings at all in the pan though. I changed the fluid it and it's fine 15k miles later so far. Regardless...the thing will die at some point. I am a firm believer that I have increased its life regardless if it is 1 day or 10 years.

That being said, you want to do the fluid exchange method to swap out the old fluid and not a FLUSH. The way to do it on these cars is to disconnect the transmission cooler line and while the car is running, let it drain into a bucket. Drain a few quarts. Stop the car. Fill a few quarts from the top of the engine, etc. Keep doing that cycle until it starts turning red again. This way you aren't putting abnormal pressure on the system like a FLUSH from the dealer would do.

-Mike