I am planning to buy a used gearbox for my Honda CRV 1999. What are the considerations I need to take into account and what are the other costs involved apart from the installation?

Unless you replaced the clutch assembly within the last 40-50K miles I would do so along with the throwout bearing. Since you will have to pull the axles, check the CV joints and boots.

. Warranty, if any.

. Use Honda Super High Temperature Urea Grease to lubricate output shaft spline, release bearing's annular groove, and release fork.

. Clutch kit--clutch disc, pressure plate, alignment tool, pilot bearing, and release bearing.

. Flywheel machining.

. Refill transmission with Honda Manual Transmission Fluid.

You will need 12-point sockets to remove the flywheel--for machining the flywheel and installing the pilot bearing. You also need a quality torque wrench and 8mm drift pin to remove/install the shift linkage's spring pin.

I assume it will be from a salvage yard and a vehicle that was wrecked. My opinion would be try to find a vehicle without front end damage which might be hard to do. Impact from collisions cause parts to be jarred around depending on the force of the collision. Also a gearbox from a vehicle with as little mileage would be best.