I have an 83 tranny & tcase in my 84 runner......

Obviously the tranny to motor is fine (mine was manual to manual) but the tranny is a bit shorter... I welded a new plate for the front most bolts on the crossmember and the rear bolted to the orig front....

Use the 83 front drive shaft - may need to drill or swap flanges. Rear if memory servs i'm using the 83 as well - I did have some DS work done but it might of been the joints....

Now for the fronts... I'm pretty sure you can use half the 83 and half the 84+..... if you compare side by side you gotta use the main shorter side (I think this is the main shaft not the slip side)...