This is an overview of how to replace a manual gearbox.
Estimated time: Full day Difficulty: Hard
You will need to jack up the vehicle as you will be working underneath. When jacking it up you will need to place blocks or jack stands underneath each corner of the vehicle to hold the weight while you work underneath.
Disconnect any electrical connections to the gearbox and remove the bolts connecting to the driveshaft. Put a mark on the driveshaft as you want to make sure that you put it back in the exact same position that you took it from.
Disconnect the bolts on the output shaft and you will need to either place something in the extension housing to stop the transmission fluid leaking out or you could put a container underneath to catch the fluid in.
You will need to disconnect the speedo cable and shift linkages and any other parts that are still connected. Make sure you remember where each part is connected. Labelling the removed parts and wires could be a good reminder.
Place a jack underneath the gearbox to take the weight so that you can disconnect this from the engine. Remove the bolts that connect to the engine and the cross member. When the gearbox is free you can pull it away from the engine, lower the jack and take it out the way.
Fitting the new gearbox
Once you have followed the instructions above you are ready to fit the new gearbox.
Place the new gearbox on the jack, slide under the vehicle and put back into position.
Re-connect the bolts holding it to the engine and the cross member, ensuring they are fitted tightly.
Now reverse the above processes to connect the other parts, wires and connections to the gearbox until everything is back in place. Top up the transmission fluid, start the engine and take for a test drive. This completes the installation.