You’d need to know if you have the M226 or C200 axle. M226 has limited availability of service parts and nissan says you’re supposed to replace axle shafts any time seals are to be replaced, which is any time the axles are removed. Probably $1000 in axle shafts if you don’t want it to leak when you’re done. If you just want to change the differential you may be able to get it done in your budget but most people change ring and pinion at the same time because your pinion depth will need to be set which means you’ll need to press off those bearings and collapsible spacer. At a minimum, if you could get seals and bearings for the shafts then those would need to be cut off or pressed off and reassembled. This is a very difficult job for even experienced mechanics and if it’s not 100% correct, then you destroy everything you’ve built.

 

I am almost positive it is a C200 axle. What are my options for that?

 

Well I’m not expert but I think ARB makes an air locker for it that runs about $1000. If you wanted to stay in your parts budget of $500, you may be able to put a Lokka or a Powertrax unit back there but if you’ve never driven a vehicle with an automatic rear locker, you may want to reconsider. It’s often inconvenient and sometimes dangerous. Read somewhere that even Lokka says that if you’re only going to get one, they recommend putting it in the front.