Valve bodies are different slightly as well as the TCC solonoid was changed from 93-94. The swap is doable though, but I can't remember off the top of my head what all is involved. I believe you need to swap out the TCC solonoid inside the pan, and there is a whole or 2 that has to be drilled. Also I'm assuming you already upgraded the plug as it changed from 93-94 as well. Also if this is a 4X4, you have to pull the trans back out and disassemble the rear section to install the output tone wheel on the output shaft. 91-93 used both an input and output speed sensor in the trans for teh ECM to shift whereas 94 eliminated the output tone wheel inside the trans as the new ECM could get by with just the sensor in the transfer case and calculte gear ratios by the 4X4 low input wire.