i am driving a nissan sentra year 1990...dunno what model is that but it's using the same engine with nissan sunny...but it's 1.5 la. now i having this problem is...the rear wheel got sound...when go tru those numpy road...and it's seriously anoying me...the sound is like something is longgar....but after checked by the mechanic...he cant detect anything wrong. sigh~just wanna ask where i can get a good mech to handle such problem ar?and one more thing is...where can i get the engine bay wash ar?bcoz it's bloody dirty lar...and i dare not to wash it...bcoz no skill...and onre more thing is...how long we have to change the gear box oils?for manual car?thanks yea...