Sale deed vs Sale agreement.

Hallo Sir/Madam,

I am looking for a home loan for 10Lakhs.My eligibility looks good.The amount mentioning in the Sale agreement is 17lakhs.But,the property worth rupees 13Lakhs.But,in the sale deed the amount wil be mentioned as 13lakhs(the actual amount).To avail the loan of 10lakhs what should I need to do.After I handover the sale deed to the bank,will the sale agreement becomes void.Is that so?.The bank will come to know the difference amount mentioned in the sale deed and sale agreement.Will be the problem to me after sanctioning the loan.how do i mitigate this ris?.Please help