I have a Chevy Tahoe that has 170,000 miles. It is time to get the transmission flushed. The garage that did it last time (almost 80,000 miles ago) is no longer in business. I have my tire rotations and oil changes done at a local Firestone, but they will not do a flush on a transmission with over 100,000 miles. They say they son't do cars with over 100K miles because they are afraid they will create a problem. I am afraid if I take it to a dealership, they will tell me there is a problem, even if one does not exist. It does need to be done; the fluid is getting dirty and it's starting to rev a little higher between gears. Should I take it AAMCO or one of the national transmission places?
Typically, transmission flushes will not be performed passed 100k miles because of excessive wear. When a flush is performed on higher mileage transmissions, it can be known to cause premature failure, this is because over time high temp and buildup can bore the existing channels larger thus creating air space that heats up and burns the transmission. Simple drain and refill with a filter change may be all you need.