Need help with rear pinion flange

[Iv Avila]

Hello,
Back again. Currently replacing gasket and fluids from rear differential on my 2007 chevy tahoe 5.3. I have never done this before but its coming out ok as of now. Currently stuck and indecisive with my rear pinion flange. What do i add on the threads/grooves to prevent fluids from leaking out of the differential. Some say grease and others say pipe sealent. Is there a specific grease to out on there or a specific pipe sealent i should be using. Any help is appreciated

 

[Fless]

FWIW those are called "splines."

 

[Iv Avila]

FWIW those are called "splines."

Thank you for the correction

 

[OR VietVet]

I have only ever had grease on the splines, during reassembly. I have never ever experienced any fluid leakage past the splines. You can also use grease on the NEW seal when reassemble.