[alamantia]

Tahoe has about 175k on the clock. I bought it 2 years ago with about 145k the weekend I bought it i took it up to my dads shop and tuned it up, install new shocks, tires, brakes and dump and replace all the fluids. After I did the oil change I grabbed the trans filter kit and all of a sudden one of the techs came over and asked me how many miles were on the truck, I said 145 he then asked how the fluid looked and smelled, i said its red and smells fine, he then advised me to leave the fluid alone. I said, isnt that just an old wives tale? He said no, another one backed him on it and my dad threw me out of the shop. Fine whatever, i left it. Lately I noticed it was banging when shifting, especially if I have been driving for a while, like if the trans was hot, so friday I pulled the dipstick out. Fluid was level and smelled fine but was all brown. I was pissed cause I wanted to change it two years ago and i was told not to. So despite their warnings I droped the pan at home, installed a new filter and 4 quarts of fresh ATF (700r4 takes 12 quarts in total) of course when i started it up the 4 quarts of fresh fluid mixed with the 8 quarts of old brown fluid but it shifts fine now. I pull teh dipstick and the fluid is still brown. I drove it up to my dads shop and asked to use the trans flush machine to suck out all the brown fluid and install fresh red fluid and again with the "i wouldnt do that if i were you" or "dont do it man" comments, so i didnt. WTF? How is dirty better than clean? Has anyone ever flushed a high mileage trans to get the brown fluid out and put red fluid in and had problems after? Anyone on here with personal experiance? I think its BS