my khyber's gear box is having problem. though shifting between gears is absolutely flawless and gear change with no hard time what-so-ever.. problem lies is on 4th and 5th gear,there is GOONJ noise from gear box.if i press clutch while going on 80 or above,all noise just vanishes which concludes the gear box is producing noise. ive changed gear oil to zic 85 or 90 ,no improvement, pour MoS2 gear oil additive by liqui moly,FAILED. so now im only left with one option, repair...what should i do? repair it or is there still anything left to try? also there is some rattle noise on rpm around 1500 to 2500,above that is no sound from gear box.mechanic said it some STAR or something like that he named gone and needs to be replaced..
PS.i do not wana change the gear box,gonna fix this one up cuz i never have had good experience with kabli stuff..