Ok...so let's say I put into service a vehicle that cost $10,000 and now a year later is worth $6,000 but needs a new transmission that would cost more than $6000 to replace (cost of parts plus labor).

Let's say I really like the car and want to fix it, but really don't want to dick with it right now and I buy 3/4 ton truck so I get to take the 179 again.

What happens in this situation? Do I have to sell the broken car in order to take the 179 depreciation again?

No.

That's good to know, so do I have to recapture anything on the old vehicle?

Found a truck but its gvwr is 6000,