you'll keep failing the rear drive shaft if you don't buy rear upper control arms to fix your pinion angle.
I have the full set of TF control arms, and I've run the stock shafts for 2 years with my 4" lift, but I think the rear has finally bit the dust. Real loud clicking and grease around the boot on the t-case side. The angle is still too great even all adjusted.
Anyone who has a stock rear shaft or even aftermarket, please let me know.