Went to change the tranny filter on my 2002 s-10 blazer (not 4 wheel drive). The seal was damaged and the cavity the seal seats in is scratched. Transmission had been slipping so with 90k miles I decided to change the filter. Have had the blazer since 83k. I'm guessing that the bad seal could be contributing. Will I be able to properly seat another seal with the scratched surfaces?

 

The cavity was most likely scratched the last time the transmission was serviced. Either while removing the OEM seal, or installing the replacement seal. Depending on how deep the scratch is, a light film of silicone RTV on the outer surface of the new seal just before installing it should take care of it. Make sure the cavity is clean & dry before installing the seal. Allow 24 hours for the RTV to cure before filling with trans fluid.