Lets look at 2 cases :
1. Your wife is co-applicant but not co-owner : In this case, you need to go back to the bank you took the loan from ; or in case you want to shift the loan to a new bank, go to the bank and explain about removing co-applicant. They will need to update their records provided you are still eligible for the loan amount without a co-applicant.
2. You wife is also the co-owner : This case is tricky. You can get your wife's name removed as a co-applicant. But the sale deed and Index 2 lists her as owner! Now, unless she gifts her share of property to you, she continues to be 50% owner (but you alone will pay the 100% loan amount). So, you can still get the loan shifted fully to your name, but I wonder how you will be able to move the property fully to your name!