just recently i put in a Y8 tranny, seller said that it was in good condition with no grinds and no cracks in casing. after installation.. test drove, ran fine until i tried to go into 4th gear.. if i shift straight from 3rd to 4th it would just grind, no engagement. only if and when i let the RPMs drop to idle will it let me go in with no grinding. AND another thing i noticed is that when not driving with the car on... you can slighly press the shifter into each gear, not forcefully but just enough to the point where you feel the engine slow down... 4th TRIES to go in. it grinds even slightly

need help asap!