The 91 740 is a lot better bet as a $1000 used car than just about any 960. The main item in its favor is that it is mechanically simple and robust, which the 960 is not. The 740 can endure considerable neglect of regular maintenance without suffering major damage, not the case with the 960. The 740 is also a lot more DIY friendly, and parts are cheaper.

Transmissions don't burn fluid. If it's losing it, there's a leak. This is not unusual in AW series automatics---it's probably coming from the output shaft seal. It can usually be repaired for a couple hundred bucks. Other than that, these transmissions are pretty much trouble-free if not horribly abused or run dry, in which case the fluid will often SMELL burned, and have a dark color. If this is the case, problems will likely not be far behind.

Gas mileage for this car will probably average in the low 20s, maybe mid to upper 20s on long trips at moderate speeds (65 and under)