Synergy 8023 - Jeep JK Control Arm Kit - Manual (Page 8)

7. We recommend that you over fill the rear differential oil when increasing the pinion
angle. The front bearing will not be submersed in oil and damage may result. You can
use an aftermarket differential cover with a higher fill plug or just add additional oil
through the vent tube fitting in the passenger side axle tube. Adding an additional 1-2 qts
of gear lube should be sufficient.