Last week the NP231 TC in my 94 Sport took a dump.

4:30 AM 3 blocks from work and BANG BANG (I thought DS U-joints) GRIND GRIND. UH-OH!
I babied it (2-3MPH) to work. GRIND GRIND BANG BANG.
Took a 1/2day and went to investigate in the daylight.

Externally...everything looked fine.
Grabbing both driveshafts and man-handling them..no undo play on either.

I removed the rear ds. Hoping that that the TC had enough in it to limp my 94 home in FWD-mode (I sealed the rear output shaft)

Assessing the situation...
Daily driver.
NEEDED.

Replace TC then worry about the old one.
I spent the money and got an "already-pulled and guaranteed" TC with approx 65,000mi.

Its in now, running fine and even shifts OUT of 4hi into 2hi without the annoying lag and thump the old one had.

TODAY:
I performed an autopsy on the dead TC.
A few pics for you all to enjoy.

TC tag:


On the autopsy table:


Pulling tailshaft housing. What's with the yellow marker???


What I found in the tailshaft housing


Where it goes--


This IS/WAS a snap-ring.
With this in pieces, the tailshaft was able to move in and out. This movement caused the binding in the internals (the BANG) then it would get pushed back too far (the GRIND)
The TC's oil pump has no teeth left. And there is alot of excess "gray-matter" inside the case.

ALL this damage caused by a $0.35 snap-ring

Well..
Rebuild completely and install a SYE?? MAYBE

 

wow and as i recall those things are on tight I have to use a special plier tool to remove and install them. Rebuilding and working on these newer transfer cases are much easier than the older "all Gear ones" which i learned on. I rebuilt many a D18. Less parts in them. and lighter to move around on the table.