I have a gsr transmission with a kaaz lsd (it requires gl-5 80w-90 gearoil, factory is equivalent to 10x-30) put well over 4000 miles on the car last year with no issues as far as grinding many 1/4 mile passes. Over winter i rebuilt the engine bored it to 2 liter so im in the break in period right now. Since i am gonna take it easy for the first 1000 miles i put in brad penn gear oil with friction additive to save on cost because the kaaz gear oil requires being changed every 4000 miles. Well i am now on the stage where i can rev the car to 4500rpm and i get a "grind" when i shift quickly shift slowly it dont do it. My question is has anyone experienced problems with running the thicker gear oil required for the kaaz or if i would just drain the gear oil in it now and put the kaaz would it fix it seeing who has any similar experiences like this......

o-yeah i also drained 1 quart of gear oil out put gm synchro mesh in still didnt do anything....

any help woul dbe appreciated