Got given this car 96 v6 te magna the other day. Drove it home just. It now only likes to go into gear sometimes when its cold but not for very long. Just slips. R,D,2,L. All the same. From reading a few of the threads on the forum this is a common problem? I found a cheap auto box out of a 4 cyl te does this fit in the v6?

Get the transmission fluid flushed, replace the external transmission filter at the top of the gearbox - if it has one - and reassess. If it still slips, I'd be looking for a new gearbox.
And no, the 4cyl boxes don't fit V6 engines.