GC D30

[DansGreyMj]

i heard that gcs have a better d30 and i wanted to swap in a non cad anyways would it bolt straight up or would i have to make any mods

[xjbubba]

I'm guessing you have an early D30? High pinion, with vacume disconnect axle? You didn't really say--
If yes, I personally think your base axle, with its high pinion is better than the GC unit, which has a low pinion.
High pinion, reverse cut gear sets are significantly stronger than standard cut gears. The GC unit probably has better axle u-joints and brakes. If (and a big IF) I were going to put money into a D30, I'd keep the early unit and swap in the GC components such as knuckles out and axles. I've seen threads regarding these mods on here and on Pirate4x4.