changing the fluid of A340F transmission

[2ndGen]

I've never changed auto trans oil before. on the A340F tranny, it has a dipstick and drain plug, do i just drain and refill or i have to do something to make sure all the fluid is out?

next, what fluid is recommended? OEM Toyota T-IV or brandname full synthetic.

thanks.

p.s. I've heard some horror stories of things happened after the "Transmission Flush". Is it a good idea or necessary for mine with 123k miles?

[avstanley]

I have done some research into changing the fluid on my auto transmission and it seems like you only get 3-4 qts out through the drain plug. This is only about a third of the fluid though. I have heard the same stories about flushing the transmission and have problems after the fact. It seems that most of the horror stories come from transmissions that are pretty worn out to start with. I have changed the fluid in mine several times by draining and filling, but have never gone the flush route.

[2ndGen]

i asked on one of the other forums about this: http://www.toyota-4runner.org/showthread.php?s=&threadid=50151

[Crinale]

i dont know if its the only way for toyotas as well, but for my honda cr-v, flushing was a big no-no... its got a built in screen filter that cleans the fluid, and flushing blows all the crap out of the filter back into the system...

we always did 3x drain and fill... drain, fill, drive for 10-15 minutes to circulate fluid, then repeat 2x more... takes more fluid, but it changes out like 97% of the old fluid... enough for honda's fairly stringent requirements... never changed the fluid on my 4runner tho, since iv only had it a month...

[Crinale]

the drain and fill sounds like it is what is recommended in option 'B' in your other forum post... although, i didnt realize it was 16 qts of fluid... probably take more than 15 minutes of driving... probably closer to 30 to circulate it well

[2ndGen]

i have not yet found out the fluid capacity of the transmission, it could be they use 16 qts of fluid in the whole process of flushing the system, not actually the capacity.

[Robinhood4x4]

If you get 16 quarts, you will be good to do the flush. Actual capacity is a little less.

There are a lot of myths about flushing auto trannies. The screen should be clean everytime you flush. You can do a DIY flush by removing supply line to the radiator and puting it into a 5 gal bucket. Then start the engine for about 5 seconds and it'll empty some of the fluid. Shut off the engine if the fluid starts to sputter. Refill at the dipstick and repeat until the fluid coming out looks new. As you can see, the fluid never reverses flow and will not back flush the screen.

Now, whether flushing kills a tranny? That one has some merit, but if your tranny is in good condition, it shouldn't matter. If it's older and has a few miles on it, it might accelerate it's demise.

Here's a blast from the past that details tranny flushes. This is the guy that started URD. http://www.gadgetonline.com/TransFlush.htm

[CJM]

I always did it like this:

1. Drain from the pan as much as possible, if it has a drain plug even easier
2. Add fluid to top it off
3. Drain again
4. Fluid to top off
5. Repeat 3 and 4 till the fluids clear.
6. Replace filter and do final fill.

Course you can always do the supply line and push out the junk stuff, basically same way those fancy machines do it. But you use a bucket.

As for the myth that you only get 3-4 qts at a time..more like 5-8 or more depending on car.

Also I swear by lucas stop slip. My old camrys trans wouldnt grab second gear if you gave it to much gas from a stop. I added that and it grabbed it decently for awhile, probably another 40k or so.

[2ndGen]

dropping the pan is probably the best method, changing out the pick-up screen while i'm there. i've read the factory manual about it, nothing fancy mechanically, but problem for me is i've never made a gasket before, with the vehicle on the ground, it's very hard to avoid nicking the gasket paste while trying to put the pan back on. well, it's very esay job having it done at a shop with it on a lift. both dealers don't drop the oil pan.

[2ndGen]

just finished the "drain 'n fill". dumpped the oil fluid in an empty oil pan, then measured with a milk jug. exactly 5 qt. refilled with same amount of Toyota T-IV. pretty simple task, even easier since i had the airbox removed to replace old spark plugs. probably i'll do it couple more times next week to dilute the oil fluid bit more.