I have the 2003 Pontiac Grand Prix GT with 110,000 miles on it. The Trans fluid has aeration in it, bubbles are showing, and it smells old, not burned though. Im going to change the fluid, so i was thinking of using Pennzoil High Mileage ATF fluid, and a bottle of Lucas Transmission Fix, to help possibly worn bands and clutches. Does this sound good or does anyone else have a better idea for fluid?

I would stick with conventional dexron 3. Usually the high milage tranny fluids are part synthetic, and I think Bob mentioned 4t65e trannys have problems with synthetics.

I also dont think I would add any additives to it, but its just my personal preference. Its up to you. In my experiences, they tend to just be wast of money anyways.

When you change it, make sure you dont overfil it, as it will cause aeration.

not rly true about that tho zzp runs dextron 5 or 6 in there and ive always used royal purple atf in there and i love the stuff only cost like $12 a qt but well worth it i think if you plan on keeping the car for some time b.c with dextron 3 it starts to break down around 40k 50k miles and turns little darker idk id say stick some money in and get the good stuff and change the filter

Yeah but ZZP has an unlimited budget on their project cars and plenty of spare replacement trannies. Different story when it is your own ride that you have to depend on for daily transportation. For me it makes no difference. I'm still waiting on a guines pig to switch over to the Dex VI and let us know how it turns out. We have had members with issues running Mobil synthetic ATF so it will vary and I would not make an assumption what is good for some is good for all. :grinno:

I stick with the good old Dextron-III and replace it earlier. My tranny has been beat to death at the track.