Its not easy to feel the shift from 4th to 5th (if its 5spd AT)
What u can do to confirm is, drive with OD off till 70 (note the rpm there), then press the OD on and note how much RPm drops and till where.... for e.g. it will go frm 3k to 1.8k RPM.....then continue to speed up till 90/100, if there is another drop of Rpm, then thats the 5th gear, otherwise 4 only.