help.. 92 blazer, trans questions..

[G35MIKE]

Hello all.. My dad just got a chev blazer 92. He's having trouble with the transmission. Basically it takes too long to shift from 1st to 2nd gear. Also to get it to shift i have to be at about 75% throttle, and be above 25 mph. Also if the truck is moving lets say at about 25-35mph, and i give it gas it will hunt for a gear and rev.

I tried messing with the tv cable, but no dice. Is the trans bad?

Also would a 700r4 trans from a v8 chevy van (86) fit this blazer?

Thanks for any help you guys can provide.