It looks like I'm going to need a little frame work on my new TJ. Connecticut rust. I suspect that when the clutch was replaced, the weld nuts in the frame had rusted out. The skid plate is now welded to my frame in some places.
Soon, I will add a product called Safe-T-Cap on the frame rails, and with that, I should go ahead with a belly up skid plate.
So for the real question, can I add an SYE with no lift?!?
Will that same SYE and cv driveshaft work if I say lift after it is installed or would I have to get a whole other for the change in hieght due to the lift
I think that's a good question. My plan was to order for a 4" lift and assume I wouldn't fully collapse the driveshaft. I also assume in stock form, I do not have the up travel I will have once lifted. I know that's a lot of assumptions, and the reality is, I don't have to do the SYE/Driveshaft early. I just know it would be easier with the skid plate off.
Replacing the stock slip yoke output with a fixed yoke is just replacing the output connection method. It doesn't care about the height of your springs as long as you follow the rules, just like anyone at any particular height should. You'll obviously need a double cardan drive shaft so that you can bolt it up to the yoke and maintain a slip section (moves from the OE 'slip yoke' rear output shaft to the drive shaft itself).
Your pinion angle needs to be inline with the drive shaft, again, regardless of spring height. Since you're adding a higher skid at the same time, it only makes sense to be doing the SYE and other associated requirements now. Even though your springs and ride height will still be stock, your t-case output relative to the frame and ground will not be. That's what matters, not height.
As for the drive shaft working in the future, it's all about the slip section. If you've got a long travel slip with plenty of engagement at full droop then you're fine. Don't go by 'lift height', go by the actual measurement from yoke to yoke. I'd ask the shaft manufacturer how long the slip sections are and what percentage they expose at ride height (the measurement you give them). You could always ask them to make the shaft a little longer to accommodate your future and current plans. Otherwise, if it eve needs it, having a drive shaft lengthened or shortened isn't hard or expensive work. Not a big deal at all.