Really want to replace the tranny fluid

(2011 5.7 crewmax)
But I'm the second owner, & it has 234k. I put some tranny fluid in a clear bottle and it's DIRTY BLACK see pic. The smell is not abnormal/ similar imo compared to my 20 Camry XLE with 25k. It drives - shifts fine when at n.o.t
I dont want to do a forced vacuum flush. I'm thinking A. flushing via the radiator line to get the most amount of fluid or B. drain & fill the pan 3 or 4 times then then replace the strainer on the last change.
My goal is to get as much of the old fluid out and replaced with new fluid where I can see a color difference. It's a Texas truck so I'm not to concerned bout the pan bolts breaking, I use to change my Tacoma fluid and filter often..
I don't know if will benefit the tranny at this point but I can't stand to leave it black n dirty.
Sidenote, being when I took possession of it I'm guessing it had been well taken care of new brakes, tires, battery, wipers, pcv valve , serpentine belt, motor oil etc. It's not a stretch to believe the P.O may have had a trany fluid service done before. I'm tempted to call the dealership with the vin that's on some of these dealer service receipts and ask about service history. Idk

 

To my knowledge there isn't a standard way to judge fluid color since the more fluid you look through the darker it appears. I.E., If you look through a clear glass cup of black coffee, it appears very dark. Spill some of that same coffee and it's now only slightly tinted. I believe this is one reason testing through an oil test lab is the way to be sure the condition of your fluid. I'd consider doing this before you decide the best option for you.

 

Do several drain and fills...it's black and smells unhealthy. A dealer can tell you if there's a record of tranny service and mileage.

 

I'd try one drain/fill then at next motor oil change do another drain/fill then do one every 3rd oil change. This will leave enough of the fine ground up debris which helps prevent slip as every transmission ages. Luck.

 

Dip a white paper towel in old fluid, then in fresh fluid...you'll see the color difference very easily. That looks black & toasty.

 

Pay attention to soot-like particles on the paper towel. If you see any that's the frictions. Torque converter produces a lot of friction wear when on last leg. Unfortunately the transmission has to be dropped for TC replacement. It also takes the valve body with it.

For illustration, ATF with bad torque converter:

 

How many miles did it have ??

 

I bought it with 207k. One ATF replacement at 110k if I remember correctly.

 

I bought my truck with 150k 3 years ago. ATF was dark, smelly and low. Leaking from pan. Dropped pan and cleaned, put in new filter and gasket. Refilled with Valvoline full synthetic and one bottle of LubeGuard. Transmission still shifts great 40k miles later.

 

I may be wrong, but I see frictions in this picture (black dots).

I once did a mistake during transmission rebuild and turned one plunger in valve body 120 degrees, which caused a pressure loss and terrible slippage in every gear. This was found after only 2-3 miles of test drive:



Had to rebuild it again, replacing the friction plates that took most of the damage, along with a new valve body.

This is not AB60, btw. AisinWarner, but for passenger cars. It's life span is much shorter than AB60.

I read somewhere a Tundra owner had to replace transmission prematurely, because he was towing a heavy boat all the time, but didn't use a tow/haul mode. The frictions were gone.

 

Bought 2019 new. Partially replaced ATF 2 years later at 21k miles. It was brown already. Replaced another time at 39k miles - same thing. The temps are 230F and up regularly. Had to install ATF cooler this year.

 

You can download the Toyota App then enter your Vin # and the truck's entire service history at any dealer will show up.

I just had mine flushed at the dealer at 216K miles.

 

I wouldn't worry to much about it being dark colored. I did a fluid exchange on mine at 120,000 miles after the dealer did a flush at 75,000 and it was already very dark. Smelled fine but I too was a bit concerned with how dark it was, I have since did another fluid exchange at 160,000 (I tow everyday) and it was also very dark. Here is the video I followed both times

(2) Toyota Tundra Comprehensive Transmission Oil Change - YouTube

 

What size hose works best to add fluid back into the transmission ??

 

For my 2017 with the AB60F transmission a 5/8" O.D. (1/2" I.D.) plastic hose is a perfect snug fit into the transmission fill hole.