Here we go again...transmission drain and refill?

Howdy folks, and I apologize for posting a thread that's probably been run ragged a few dozen times before, but since I couldn't find info close to my situation, I figured I would brave the barbs and sneers and post it again:

I have a 2003 Tundra Access Cab with the 4.7L V8 and automatic transmission. The truck has 166K on the original engine and transmission. I recently had the front struts replaced and while the mechanic was doing the normal fluids check and fill, he mentioned that my tranny fluid looked a bit brown and that I should think of doing a drain and refill (at least he didn't utter the dreaded "flush"). When I checked the fluid myself off the dipstick on a white paper towel, the fluid is definitely not pinkish but I wouldn't say it's coffee brown either, and it doesn't feel gritty.

I bought the truck used from a Toyota dealer with 79K on it, and the only major work I've had done on the engine was having the timing belt/water pump changed at 100K. Most fluids (except tranny fluid...I don't know why) I have changed myself on schedule. I do not know if the dealer replaced the transmission fluid before they sold the truck to me (this was easily over 15 years ago). I use public transit to commute to work, so I probably put less than 3,000 miles a year on the truck now.

Should I have my mechanic do a drain and refill at this point or should I leave the fluid as is? I have no shifting issues whatsoever (knock on wood) and definitely don't want to introduce any at this late juncture. I probably won't be keeping the truck for more than another 4 or 5 years, as I'm eyeing one of the 2023-24 Tundras for sometime next year possibly. Thoughts?

 

Yes. It's a recommended fluid exchange by the manufacturer ever 30k miles.

Yes, again, as the new owner will appreciate that you've done the maintenance.

 

Drain and fill is the way to go.

Or if you have a BG shop near you and are willing to pay them to do a full fluid exchange, they not only offer the service, but they warranty your transmission after. Their process and fluids meet or exceed OEM spec, which is why they're confident enough to warranty after the service, and you have few enough miles they'd probably do it.

BG Shop finder: https://bgfindashop.com/shop-locator/

 

this really doesnt get enough attention, and should be clarified more commonly, you do 4-6 d&f’s over 4-6 oil changes, or skip an OC & fill it every other? Eff it, do all six within a fuel range of 300 miles? Is there consensus on a timeline?

 

Get a Blackstone oil analysis kit headed your way. Take a sample during your first D&F and let the pros tell you how to proceed.