I have an 03 GT and 04 V6 both manual. I have done a little bit of research on the Tr-3650 and T-5 transmissions using Syncromesh oil and having positive effects but have never came across if it's actually safe being used in these transmissions. A few months ago I bought some Valvoline Syncromesh MTF (same part numbers as Penzoil Syncromesh and GM Syncromesh) and put in my 03 GT and as it seems to be liking it, I am still skeptical if it is actually safe to use without damaging the transmission in the long run. Some people have said it can damage carbon syncros over time. Any advise is appreciated.