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.

 

[rdezs]

For years, I've used a little RTV on the splines to prevent gear oil from working up the splines. Actually what Borg Warner shop manuals used to call for on the output shaft flanges on transfer cases. It's Not unusual over the last 20 years to find the flange nut has a rubberized coating under it to accomplish the same thing. For example, the crankshaft bolt on the LS engine has a rubberized coating under the flange for this purpose. If you use the RTV, you don't need to coat the whole length of the splines. Only about a quarter inch section in a circle around the shaft.

 

[alpha_omega]

Old thread but I will add this for any future researchers. On my rear pinion flange/yoke it had a white RTV sealant. More than likely it’s the ACDelco RTV used on the drain/fill plugs for the transfer case. Part No. 19333513