The part is just a few bucks if you have to change it. The low speed clutches are probably worn too, and B2 piston is worn too. You can go in just fix the o-ring, but the transmission has to come out. On the first thread, the guy who started the thread was 18 year-old, and did the job him self. Here is a thread on how to remove the transmission if you elect to do the job your self.
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