I got a 1980 toyota 4x4 pick-up got the 20r four cylinder and the l43 tranny 4 speed. The l43 is no good. Like to put a 5 speed in it how hard is it?

Yes, the '82 trans would be a great upgrade
Especially if it has the 80 mm front bearing.

You will need to do a number of changes to install the trans.
1. Two lower bellhousing bolts, they are longer.
2. '81-'95 clutch slave cylinder. [Do not reuse the orginal fork return spring.]
3. '81 and newer release bearing with collar and fork.
3. Trim floor board as required to convert to the top shifting L52 trans. [The old L43 was a right hand, side shifting 4 speed.]
4. To match the transmission output coupler, the oversized transfer case input splines will need to be ground for clearance.

Marlin