I just got done changing my Transmission and Rear Diff. fluid in my 2003 350z. This car has 22,000 miles on it, an LSD, and 6-spd manual gear box and thus far has been in good condition. I did have the standard 03' 3rd gear grinding when it's cold thing.

I chose to use royal purple's max gear 75w-90 fluid in both my transmission and my rear diff and now all of a sudden EVERY shift I make into 3rd and 4th grinds. What in the holy blue hell did I do? I just paid over 100 dollars for fluid that seemingly made my tranny worse.

Any suggestions as to a fluid change or I was actually thinking a quart of lucas trans fix fluid would help out.

 

CD009 Transmission.