Have a problem with grease on clothes. I think it is coming up from the gear box. How big of a job is it to replace the seals in the gear case?

have a problem with grease on clothes. i think it is coming up from the gear box. how big of a job is it to replace the seals in the gear case?
At least the top load washer I have has no seal. Just seams that it is sealed by pressure. Might have a broken peace right above the gear box going up the shaft. It has a lot of dark brown grease in it that is going back up the shaft. Don't see any other way for that oil to get in there.