The front differential in my STREET-DRIVEN 94 AWD Legacy wagon with 4EAT auto tranny has shed teeth at 170k miles but I have a FWD/auto trans Legacy sedan parts car (sans engine but with half the miles) sitting on a trailer waiting for its trip to the crusher. Based on available research the torque split in the AWD wagon is 90/10 (which would explain why the thing has acted like a FWD car on ice/snow) and the front diff's gear ratio is 3.90/1 while the ratio in the FWD car's is reportedly 3.70/1. I read that there's some kind of gearing in the transfer case that allows the wagon's rear diff ratio to be 4.11/1 so I'm a bit concerned about replacing the wagon's diff with the 3.70 from the sedan. Since using parts at hand rather than spending money is the TOP PRIORITY I'm juggling two plans of attack and would appreciate expert opinion on which will likely work best. Of course, either will require yanking both transaxle assemblies so the decision boils down to replacing the broken diff with the lower ratio one while retaining the AWD arrangement (counting on the 90/10 torque split from a really worn center diff to effectively negate complications from the gear ratio mismatch) or replacing the entire AWD transaxle assembly with the FWD one and just leave the rear diff driveshaft-less. I'm leaning toward the former since I have new front halfshafts under the wagon now and will need to replace at least one of those from the sedan (yes, they are different for some reason) and I'm not contemplating FWDing the rear half of the car since the wagon has new rear struts that are different from the sedan's (unless there's a market for the rear diff/halfshafts/etc that would offset the work swapping stuff and the cost of new rear struts).
So whattaya think? Am I likely to regret bombing around in a wagon with a 3.70 front diff/AWD/minuscule F/R torque split or should I create a true FWD wagon that burns a little extra fuel hauling around & spinning the rear third-member assembly?
