Ok so I finally did my t-case fluid and a good thing too, the fluid that came out was no joke blacker than my oil after 5k. BUT while i was letting that nasty fluid drain I decided to grease all my fittings. This cause me to notice that my front drive shaft has play. Not in the u-joints but at the slip yoke thing in the middle, it can move about an 1/8" in any direction! So obvious that needs replacing right? And from a stop when i accelerate I hear a thud thud thud, usually 2-5 thuds, then it goes away. AND when I come to a complete stop, the second it lurches back, I hear one more loud right under my feet. So is this the problem, I need a new DS?

sounds like it to me but i would take it to a driveshaft shop and tell them what you found and ask their opinion. ask their mechanic though, not hte guy at the desk cause he will only tell you that you need a new drivesahft

I would say easiest way to check would be to remove the ds and take a drive....i also would guess the issue and sound are related though.

So if the rearend lurches would that be the rear drive shaft?

No its the front, The lurch im talking about is when you come to a complete stop. the best thing I can compare it to is what cops look for to see if you come to a complete stop at a stop sign. After thinking about it, Im wonder is when it goes to settle after stopping, the axle is somehow putting load on the DS but not radially, load where the ds would want to bow.

look at the rear driveshaft slipyoke. removed the dust boot, the rear driveshaft then clean and lube the splines. i believe there a tsb to use a teflon lubricant on the splines to stop the noise tht you are hearing. don't go crazy with the lube either, that will cause the noise as well.

my front driveshaft probly has more play than an 1/8th of an inch and i just lubed my rear slip yoke with wheel bearing grease but didn't slop it on. i don't get these noises. if i ever due i'll switch the wheel bearing grease to the tflon stuff.

good luck and let me know if that solves your problem.