today replaced gear oil with zic. bought 3 bottles of 1 ltr each and poured in 2.5 ltr. mechanic was asking to pour 3 ltr but i trust pakwheelers more than mechanic 
will get to know about noise tomorrow morning, previously it started a very little noise when even warm but after replacing no noise. hope so it works for me in morning.
Also got engine tuning done.
