Mmm... don't know of anything specific. You could ask on www.ifsja.org
- there's more Quadratrac experience there.
The Quadratrac reduction unit just unbolts and comes off - no great trick to it. Take a look at the 1976 Jeep FSM here http://oljeep.com/gw/76_tsm/Section8.pdf
- a '76 is the same as a '77 wrt transfer case. Note there are shifting instructions there too, that tell you how to put enoguh slack in the drivetrain so it will shift. The output shaft may have worn a little step that makes shifting difficult - you could try the Jeep shifting procedure, just to make sure. They are known to clunk due to wear on the transmission output shaft, but I don't think that will prevent shifting.
The reduction unit is pretty simple, a planetary transmission. There is a collar inside the case that slides and either locks or allows the planetary gears to turn. The previous rebuilder may have put it together wrong. I would expect it to shift easily on the bench.
1) '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps. 2) '82 J20 360/T18/NP208/3.73, KOs, 7600 GVWR 3) '75 CJ-6, 304/T15, PS, BFG KM2s, soft top 4) '95 VW Golf Sport 2000cc 2D