Advice needed on high mileage transmission oil change.

I vote for a drain and fill and a magnefine filter, if all goes good do another in a few hundred miles and maybe a full flush later. Iirc a member flushed his not to long ago with 140k and his is fine. I've done a lot of reading over at bobistheoilguy and most of them agree that if a flush kills a transmission it was gonna die soon anyways. The flush is pretty easy and not much more involved than a DIY drain and fill, it's your truck and your call OP.

 

https://www.tacomaworld.com/index.php?threads/DIY:-Full-Flush-for-Automatic-Transmission.68462/
See post 334

 

i spoke to a shop near me. my truck only has 35k original miles from 06. they said DO NOT FLUSH THE TRANNY, they usually will do 50/50 old to new if you want a service. Since the tranny fluid is highly detergent it can break down deposits that may be allowing a shitty tranny to work normally or close to it. i would assume a perfect tranny would handle this fine but if there is high mileage or intense use then maybe wait until it needs to be done...

i have never touched the tranny fluid on any car i owned bc the tranny felt fine.

 

The way we "flush" our transmissions is by simply letting the pump push the old fluid out while you're adding new, it isn't a pressurized flush or back flush like some shops used to do. I've used the cooler line method on several of our vehicles including a trailblazer with a 4L60-e, which is a transmission that is known to be problematic, knock on wood it's still fine. Btw I flushed it when it was 10 years old with 50,000 miles on the factory fill. The original fluid was still pinkish, just starting to turn a little brown, but didn't smell burnt. I'm gonna drop the pan for the next service and change the filter and install a Dorman pan with a drain plug and do an annual drain and fill until it reaches 100k, then I'll change the filter again.

 

I was the shop manager for the largest transmission shop in Maryland for many years and honestly I have seen many high mileage transmissions fail after a fluid change it is best to leave a working transmission alone when the mileage is high.

 

I have an 08 Tacoma with 204,000 miles and never changed the trans fluid...LEAVE IT BE

 

I was just reading all the threads. Thanks . My 08 has 204, as well an it's running fine. I was just inquiring cuz some1 told me not to mess with it.

 

I had the dealer change it mine at 176k I'm not sure what that is in tailed with the dealer doing it but hopefully it's fine and so far it has been fine. Knock on wood!

 

I see your point, but I imagine those trans. were having problems that made them come in, the new fluid just finished them off...