just changed my fluid today i had no issues with grinding before other than down shifting to 5th.
now in high rpms (6-7k) shifting from 3rd to 4th there is a grind in 4th.
i used royal purple max gear 75w-90 it says on the bottle for gl-5 and gl-4 (in tranny and rear diff)

 

can anyone help only question i need answered is it because i used max gear instead of synchromax in transmission

 

Known issue, you should have researched the topic before choosing RP. I only use and recommend OEM tranny and diff fluid.

 

i just bought rx8 2010 with manual transmission the clutch is light, according to the madza dealer that normal to madza manual transmission. is just like to know if that how the clutch feel on rx 8.