Sounds like your transmission bearings are shot. It doesnt make noise in 4th gear because its a 1:1 straight through drive ratio and the affected gears are not spinning. Not sure what the noise in neutral would be.


'04 Taco x-cab 3RZ FE stock (daily driver)
'90 x-cab 22RE stock
'82 Hilux 6" lift (ACES HI)
'82 2-Hiluxs' Rally Edition (parts)
'81 Hilux 3" lift (parts/restore)