Yes, remove the old filter pick-up bore seal. I install a vette servo on every 700R4 I rebuild. Just follow the instructions that come with the Transgo shift kit and check for / adjust band clearance as needed.
You shouldn't see more than 1/8" longitudinal travel of the band along the reverse input drum...Take the old servo assembly out, reassemble everything with the new Corvette servo and leave both the blue and red o-rings and large, front scarf cut sealing ring off the assembly...
Procedure
Install it into the bore like that (make sure you put the main spring back on the front of the assembly) then install the snap ring. From there, push in on the servo cover and see how much travel you have...Ideally, you should have between .045-.090. You can mount a dial indicator to the case to measure this or simply go by eye or use .050. and .093 drill bits that come in the shift kit as a 'gauge' to measure inboard travel...Then spin the output shaft counter-clockwise to make sure the drum isn't dragging on the band...Take a flat blade screw driver and gently move the band front to back, back to front and visually assess travel...1/8"-3/16" is your target.
Once dialed in, remove the assembly, lube the bore, install all the sealing rings/o-rings and reinstall for the final time - you should be good to go.
