Will I need a new tune??

[97xl]

My first post but I know some of you from other forums. Anyway on to my issue.

First the truck info/bolt-on mods I've done so far.

97 XL 4.2L V6 4r70w 3.08 Non LS, General Grabber UHP 265/70r16s, AF1 CAI, ASP UDP, Cherry Bomb Vortex SIDO catback, Maggie Hiflow Cats, Troyer tuned 94 performance.

Now the issue I have is after lowering the rear 2" with drop shackles the truck has developed a very slight bouncy feel. Had them check the pinion angle and it's only 0.5 degrees off which is ok. My mechanic took off the inspection cover of the rear diff and the spider gears badly pitted, one even has a visible crack and they have waayyyy too much play in them. I was hoping to put this mod off until next year but seeing that crack makes me nervous. So I've ordered a Tru-Trac LS and 3.73 gears.

My question is since my Troyer tune was made for the 3.08s & open diff will I need to get a new tune or could I make the changes with the Xcal3? I'd normally stick with the same tuner but I don't want to drive 10+ weeks with the wrong tune.