This is a Rear Axle with Open Differential that was introduced in the D64 and D64-1. While it's compatible with all current WPL models, the drive shaft that came with it may not be the compatible length to your WPL model. You may detach the drive shaft from it and install your existing drive shaft onto this axle and it should be good to go.

Open differential works well for onroad driving as it allows your WPL to turn or corner smoothly however it's not recommended for crawling as you want equal power transfer to all 4 wheels without slipping.

Price is for 1 piece of Open Diff Rear Axle as shown.

Metal diff gear and input gear