Rear end rebuild - break in before synthetic oil?

[Rocket]

Just wondering if you would recommend using conventional oil to break in a rebuild differential center section before switching to synthetic. I will most likely use the old gears and just new bearings in the center and axles. I was planning on using the synthetic right away given these are not new gears. If new gears are used is the process different?

If the conventional oil is used first, is there a way to pump the old oil out or do you need to pull the pumpkin to get it out? I have always pulled the pumpkin.

Thanks

 

[ted_sweet]

suction pump

 

[fishy68]

It will be no problem going with the synthetic right off the bat.