Re: What do I got? 1980 cherokee
With the shift UNDER the driver seat... sounds like there is only one choice there.... BW1339 Quadratrac Unit with low range. This unit was ONLY mounted to a TH400. Since you should have the TH400/QT combo... it is mostly likely to have the Dana 44 up front (30 spline pass side diff) and the QT offset Dana 44 rear (also 30 spline pass side diff).
axles may have 3.54's or 3.31's...dunno if they had any other gear options than that.... but the front id open and back MAY have a LSD diff but not likely....
14" total lift