Hi,
Currently i am on H4 visa and applied H1B(Premium) in 2013 quota on 6th of June. Before my H1B got approved i have to transfer my H4 visa as my wife is joining a new company.
Can i transfer my H4 visa without having any problems while my H1B is under processing?
I think you may transfer your H4, without any issues for your H1B petition, since you are not changing your H4 status.
H-4 status is dependent on H-1 visa and not on the employer. So as long as you have valid I-94 and your spuse is maintaining valid H-1 status through his employer, you should be fine. H-4 visa is not transferrable like H-1.
I would suggest against getting H-4 extension filed through new employer as then Last Action Rule comes into picture. Let your H-1 get processed and in case it gets denied, then only go for H-4 extension through new employer.