How do you change the rear main seal on a 2000chevrolet silverado?

I own a repair shop and it is very rare, 2 times in 20 years, that I have had to replace e rear main seal. It has been that our analysis to actually be the PCV, Positive Crankcase Ventilation, system to be inoperatable. The PCV system prevents crankcase pressure from building and forcing oil out at the weakest point.

Find a good repair shop and have them repair the PCV system. It consists of more than just a pcv valve.The system HAS to take in fresh outside air in order for it to work properly. You should feel a suction on the inlet side and that will let you know that the system is venting. One sure sign that it is not working is oil in or on the air filter. Clean both areas down real good with brake cleaner as it will not leave a residue.Get that working properly and wait a couple of weeks before even considering replacing the SEAL. Some places would rather replace the seal than repair the pcv system as it pays more money.

If that doesn't work then repost your question and I will be happy to further assist you.