1995 Infinity G20

Im thinking of purchasing this car for a project,its for sale locally and its a pretty nice car. 106k miles and it runs fine.
The problem is it wont go into 3rd gear 1st 2nd are good and reverse is too but no 3rd...what are some other things that could be worng beside the tranny being SHOT and if the tranny is about how much would i be payin a guy to rebuild it? Could i do it myself (family has lots of experience in auto but not me).

And i also im lookign a a white infinity that has a blown piston and needs a rebuild kit for the motor.....

 

you don't say whther it's automatic or manual...but in either case, unless you have a very experienced family member to help you with this, the trans is probably not a good DIY challenge. have a good look at the fluid, does it smell burnt, look very dark, can't see thru it? if so, something hydraulic has given up in the direct circuit and it needs rebuilt...expect to pay a couple grand retail. if the fluid is clean and clear, expect something broken mechanically...might be alot cheaper to fix altho you could have trouble finding someone to open it up and not O/H it based on mileage. either way...most likely an expensive endeavour.