Here's why it's so complex and what's involved:
* Transmission Swap: You need to source a suitable manual transmission from a donor 1991 Subaru Legacy (or potentially a compatible model year) with all-wheel drive and a turbocharged engine. This transmission must be in good working condition. Simply bolting it in is not sufficient.
* Clutch System: This includes the clutch pedal assembly (requiring modifications to the firewall and possibly the floor), clutch master and slave cylinders, clutch lines, pressure plate, clutch disc, and throw-out bearing. These parts are all specific to the chosen manual transmission and the car's year/model.
* Driveshafts: The driveshafts might need modification or replacement, depending on whether the donor transmission's output shafts match the automatic's.
* Shift Linkage: The entire shift linkage, including the shifter, cables (or rods), and linkage mechanisms, must be installed and properly adjusted.
* Computer/ECU Modifications: The automatic transmission's computer control system likely needs to be reprogrammed or bypassed, as the engine management system is designed to interact with the automatic transmission. This might require professional tuning or a custom solution.
* Wiring Harness: Modifications to the wiring harness are almost certainly necessary to accommodate the clutch switch, reverse lights, and potentially other sensor inputs.
* Hydraulics: The hydraulic lines and components associated with the automatic transmission need to be removed and replaced with the appropriate manual transmission components.
* Differential: While less likely, there's a chance the differential ratios might differ slightly between automatic and manual models, requiring attention.
* Exhaust System: Depending on the specifics, some exhaust components may need adjustment.
In short: This is a major mechanical overhaul requiring extensive mechanical experience, specialized tools, and access to parts. It's a project best undertaken by a skilled mechanic familiar with Subaru all-wheel-drive systems. Attempting it without this expertise could result in significant damage to your vehicle and potentially injury.
Instead of attempting this conversion yourself, consider looking for a used 1991 Subaru Legacy already equipped with a manual transmission. This is significantly less expensive and much less risky than attempting the conversion.
