Join Date: Mar 2007
Location: Hickman Nebraska
if its never been changed at all, yeah putting new fluid in it(definatly syn fluid) may cause problems. it couldn't hurt to do it i suppose, especially at 150,000. at that millage with no fluid change, your probably headed for a rebuild/replace really soon anyway, might get you a few extra thousand miles.
I'd go for it, drop the pan change the filter, drain the T/C, and fill it with some mercon, maybe not the mercV might be a waste if it blows up later, but if your not having problems with slippage that couldn't hurt either. MercV will stop the vibration problems these trans get. make sure you don't put Dextron(GM brand) in it... seems to kill these trans, or at the very least make the T/C vibrate.
long story short, filters and fluid are cheep "shrug" might as well... if it gives you an extra 20000 miles, it was worth it.