Managed to put the new o-ring in with BoiseBenz help. You need a lot of patience as the clearance to remove the old o-ring is very limited. I broke the lip of the B2 reaction piston. It was made of plastic and was very brittle and when I tried to push the piston inside the tranny, it broke. It is the black color part on the right in the picture. The linkage inside is still in place. The broken plastic lip is very flimsy and is nothing like what is in the part's picture. I hope it should be OK unless you advise me otherwise.
When I did the o-ring I need to
1) Remove the metal strip which goes on the ratchet notches.
2) Remove the shifter shaft
I took some pictures before I did the work but it does not show clearly which notches in the ratchet is 'Park' position. Basically I need info to put the tip of the metal strip back into the right notch.
Any info is appreciated.