I have an 84 toyota with dual t-cases. It keeps kicking out of 4 low, any ideas?

I would check the clearance of your shifters in the floor first.If the hole is not big enough the shifters will hit and it wont go in all the way. If you have a bodylift the boots could be binding it up also.

x 2. there are other possibilities too. worn bearings cause shaft misalingment which can cause that. another thing that i have seen cause this repeatedly is a long shifter or heavy shift knob. the extra leverage and mass will yank things out of gear when the trail gets bumpy. i cured it on one rig by making a wooden shift knob that weighed 1/4 as much as the stock peice. never acted up again.