06 Tacoma ATF chang

I've sent a lot of time reading about changing the tranny oil or not and when for my '06. I'm inclined to a DIY job as explained on these forums. But that got me to wonder why not do it in several, repeated steps?

Rather than unhooking the cooler line and carefully draining a jug at at time and then adding a equal amount in that method, why not simply drain the pan cold (about 3.3gal.) add that exact same amount back into the system and go drive it for a week.

Next weekend or so do the same for about four weekends in a row? That would give the old sludge a better chance of getting outta there than doing the job all in one short spell. It would mean getting under there several times in a month but that aspect doesn't bother me.

Where have I gone wrong here?

 

You may have meant 3.3 qts. - not 3.3 gals. There are all sorts of opinions about this. What you are considering is known as a rotation drain. This is how it was done on 80s Honda's. They held 6 qts. - you could only drain 3. My '87 Accord had 375,000 miles on the clock when I sold it. The car never had a complete transmission fluid flush.

My wifes '06 Toyota Avalon holds 7 qts. - drains 3.7qts. I drain 3.7 qts. every 25K. Screw Toyota's 100K interval. Car is pushing 200,000 miles and transmission is quite and shifts smoothly.

I only consider rotation drains if I can get 1/2 or more of the fluid out draining the pan. I believe these 2nd Gen Tacoma's hold 10-12 qts. of transmission fluid. I don't think you are going to get 5-6 qts drained from just the pan on one of these models.
Because of that, I would use the techniques shown in 2 different threads here. One for draining/refilling with temp at correct level and the thread that covers flushing.