When do I refinance my vehicle?

Hey

I have a ~34k vehicle loan @ 16.5% APR, 4 on-time payments made. When I got the truck, my score was ~580 due to high utilization at the time. Now it's back up to 700. Should I wait until 6 on-time payments, or go for it now? I know most credit unions want 6-monthly payments, but this $775 vehicle payment is killing me. I'm hoping to refinance it around 8-10%.

I recently paid off all of my revolving debt, which caused my score to shoot back up. Single dad to a 2-year-old, I make ~61k/year, and I'm a homeowner. 18+ year credit history with a "very good" credit mix, a couple of late payments reporting, and one $1000 collection for a medical bill that is fairly recent (haven't gotten around to settling it yet). This is according to online credit trackers. I owe about $76k on my house, $6,000 in personal loans, and $0 in CC debt ($12,000 available, $0 balances).

Chances of approval for a refinance, or wait until 6 monthly payments reporting?