Should I pay off current car loan before financing new car loan with TFS?

[Mikey41]

I was18 years old and financed my first car with TFS. I am going to buy a new car in August; at that time I will owe $5000 on my car. I heard that paying off the car loan may affect my credit score but I want to improve my score from 708 to get a 0% or 1.9% APR from TFS again.  I also will have $3000 cash downpayment. Should I try finance with the existing loan or pay off loan before August then finance car?

Condition: USED Scion Xa 2006

APR: 7.54

Down Payment: $4000

Monthly Payment: $238

Term: 48 months

Total Finance: 9854

Credit Score: 627

I was delighted because no one consigned and I knew I could've afforded any car payment with my steady job.

[Dustink]

If you are trading the car in and it is worth more than what you owe, don't worry about it.

Being a returning customer with a 700+ score. You should be golden. Don't accept anything worse than promo terms.

[Mikey41]

I want to give the car to my little sister so that. I dont want to give up the car since its a good deal. Back then my parents refused to cosigned the car so I took any loan and rate from them but this time I will hustle them or leave the dealership without their car. 

Thanks for the advice!

[Dustink]

If you are keeping the car. Your current payment will count against you DTI wise. If your income covers both payments, you have nothing to worry about.

[Dustink]

If you want to pay it off, pay it off. No reason to be paying interest if you don't need to.

If your score dips, it will quickly recover.