04 with 106k. Car shifhting fine
I took car to local lexus dealer figured id have it partially drained and refilled
they test drove it and all was fine
Took a sample of fluid and said it was "too burnt" and not to change it
I saw the sample it was black and had smell to it I guess hard to tell by using nose to gauge condition

Should I leave or change half out myself

 

Not quite sure how to judge "burnt," but I have now concluded if burnt, leave alone.....I had my first drain/fill done in the mid 80's, and was told by the indie, not a chance I could ruin the tranny by doing so, based on mileage. So I did it. They said prolly need 3X to be effective, just come back when convenient. Last time I think around 89k, I went back for #2. The tech set aside what came out from the #2 drain/fill, and he proceeded to do that, drop the car, drive it, put it back on the lift, and do #3 with no extra labor. I have to admit, #2 fluid was pretty dark. I believe that's 53% new, 47% old based on that Toyota chart. By #3 I think 17% old fluid is in there--he told me don't worry about it for another 15k.....

So if original I can only imagine how black it would be, but it sounds like yours should be left alone. I'm just surprised, though, that it's already burnt, I would have thought 100k is still ok to drain/fill....my .02

 

I would get a second opinion...
Many people here have varying thoughts on this subject. If you choose to do it yourself don't change "half" the fluid. Introduce new fluid slowly and incrementally by either draining just the pan or draining a measured quart or 2 at a time and replacing that exact amount. The pan holds approx 2 quarts so the end result is about the same. Getting the level correct can be tricky without a dipstick so proceed with caution.
I recommend reading this entire thread, yes it's long, very informative though - https://www.clublexus.com/forums/ls-...er-thread.html
I call it the "Can of Worms" thread!

 

I'm looking at transmission change right now as well and I came across this YouTube video. I think it's pretty good at why they recommend not changing if burnt. I'm not 100% sure I still wouldn't do a drain and refill but I can see where you wouldn't want to do a flush.

 

I was told at my dealership to never do a flush on these cars. Said any kind of pressure put on the system with a flush can cause issues with the torque converter. Only drain and refill.

 

True. Same goes for most cars.