since its a 2.5 your best bet would be to pick up a new case/engine block from ebay. They 99% of the time already ahve the bearings in the block and people are always parting out new 2.5's on ebay.

Other than that your only other option is to dissasemble the entire engine then heat the block and pop out the bearing and replace them.

edit... in fact here are a few 2.5 cases on ebay.

http://search.ebay.com/traxxas-2-5-c...202Q2e5Q20case