I built this case about 5 years ago, so I'm going by memory. Go easy on me, I'll probably miss something and have to add to it later.
To build a 13-52 you need:
13-54e front case
13-50m rear case(no mods needed) or mod a 13-54e rear case
Either 13-50 or 13-54 adapter plate and input shaft(more on this later)
Completely disassemble and clean both cases.
The 13-54e front case will have a part of a hole where it needs to be drilled to accept the shift shaft. Drill that hole all the way through. I dont remember the size, but it has to be drilled undersized and reamed to the size of the shift shaft. It MUST be reamed to the final size, the bore must be smooth seal. The shift shaft has an o-ring to seal this hole.
You will not be able to do this next mod on all 13-54's , but there is a way to make it work anyway. Install the shift shaft and internal linkage from the 13-50 into the new hole in the 13-54. You will see that the 13-54 case is thicker where the shaft goes through the case. measure the difference in thickness (you need to be very accurate with this measurment).
1) Some cases have more material then others. If you can, The easiest way is to grind down the case (90° to the new hole you just drilled and reamed), by the amount you just measured.
2) If there isnt enough material, install the shaft and internal linkage. Put the external shifter arm on ( in the correct orientation) and tack weld in place. Be sure its in the right spot, before you weld it.
The last hole that needs to be drilled in the front case half is for the detent and spring. This can be done 1 of 2 ways:
1) Drill from the top down. The manual case has a sensor to illuminate the 4x4 lights. You can drill the case for this sensor, then drill farther down into the case for the detent and spring. (this will make sense when you have the cases apart).
2) drill the case from the bottom up. Drill the detent hole all the way through on the manual case. This will show you where to drill on the electric case. Drill the hole in the same place as the manual case. Tap the hole about 1/2" deep to 1/8" pipe. This will allow you to install the detent and spring form the bottom and hold it and seal it with a 1/8" pipe plug.
I chose #2. I dont need a sensor to tell me when I put the shifter into 4x4 or low, and it was easier that way.
Now, we have the front case half modified. Next we have to make a few choices. Did the 13-54 have a 6 gear or 4 gear planetary setup?
If your answer is 6 gear, use it. Its a little stronger. You must use the front adapter plate, planet gear/ input shaft, shift fork, and gear from either the 6 or 4 gear setup. If I remember correctly, they have to be kept as a set.
The 13-50 has an aluminum 2/4wheel shift fork, the 13-54 has a plastic one. They are interchangeable. I chose to use the 13-50's aluminum one, I believe its stronger.
Now that you know this case inside and out, use your new found knowledge and reassemble it and hope it works! Sounds easy right?
STEEV--- Its your T-case, you got anything to add?
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