I want to get better economy out of the ute, and I'm looking to change the diff. I've got a '98 XH II Tradesman. It's running a 5 speed manual and I'm pretty sure its got a 3.23:1 ratio diff (110km/h at about 2000rpm).

What I'm looking at an LSD either 2.77 or 2.92. Does anyone know if I will lose too much torque dropping this far when I've got a load in the back?

The biggest question is whether i can just slip the diff itself into my axle? whether it hooks into the tailshaft and the axles alright (splines etc)?

Cheers.