ITC claim previous year under GTA

Some where we inquired, and get suggested that as per rules a truck life is 5 years, that means 20% per year or 5 % per qtr so you can claim but since we are in September you need to changeover FCM in April and 15% less claim in next year from actual, is it possible? Please suggest.

Yes under transport agency 

is there section 18(6) of the cgst with rule 44 and 46 not applicable on transport capital goods (truck)?

Refer Section 18(1)(d), and follow subject to Section 18(2).