Hello I have 2008 sicon TC 190k the transmission service was done at 90K should I do it again or just leave it ? I check the color and it is no longer red the dealer told me not to do it what are your thoughts thanks
100k is too long to go without transmission service. You should be doing it twice as often if you want your transmission to last.
I bought my 2005 Matrix at 191k and the transmission was serviced at 90k. The fluid was dark, but still had red in it. I did several drain and fills over a couple thousand miles, and now at 219k it shifts terrific.
Not sure how hard yours was driven, the tranny could be in worse shape.
If you want a safer way to change the fluid than a drain and fill, you could do a full fluid exchange and keep the old fluid. If you have issues, you can put the old stuff back in. If you have issues, the trans was likely already going out anyway.
You take a risk leaving it, or changing it. With Toyota, I chose to risk changing it.
the dealer said not to do it might have issues after not sure what to do
don't listen to dealers. Talk to a reputable transmission shop.