hey guys I'll be swapping trans on my 02 Lt ext. & wondering about upgrades before install? It came from a 95k 02 tb. (non ext). I do have a transgo close by.
Transgo Kit as you stated, Sonnax 4th gear super hold servo, Borg Warner Hi-Energy clutch pack, Borg Warner Hi-Energy 2-4 Band , Beast Sunshell, Fordward & Rear 5(or 6!)-Pinion Planetaries, deep transmission pan.
Only thing I've ever done to any of my 4L60E transmissions is valve body upgrades (Transgo kit, sonnax accumulators, etc, hardened separator plate, etc). I've never touched the mechanical guts, and having had 215k on one, and currently 185k and counting on another, and 170k-something and counting on another, I'm not inclined to dig much into the guts.
I vote for the Corvette Servo upgrade. I did this to my used replacement trans in the 2004 5.3 XUV. I installed it in the original trans after it started failing at 198.000, It didn't help much and It failed completely soon after. Decided to install in the 100k used trans as it was replaced. I like the firmer shifts.