help with noise

89 aw4 np231 8.25 d30 2" lift
Ok, Ive had grinding noise with light throttle at speed ive been tracking down for, oh.. 5months or so. It happens at 35+ mostly. My pinion angles are within 1* and I have no vibration. New u joints, swapped d35 to 8.25, used the d35 shaft so I have plenty of slip yoke engagement, with a YJ yoke. Tcase overhauled with 6pinion planetary, shift fork, tail shaft bushing. New motor and trans mount.
I thought its been driveline issue all a long, but now im thinking something else like flexplate.
I don't have any terrible noise at idle, start up, dropping into gear etc. I have the grinding noise while driving and I can kind of get it to do it if I get up to speed, shift to neutral and hover the throttle up a bit. Also, if im cruising and I snap the throttle and let off quickly I get a very audible clacking noise from mid vehicle. Its nasty.
The other day I wheeled around cline butte for a while, once I got back on the highway it wasn't as bad as it has been, almost not there. I didn't try to get it to make the clacking noise tho. The next day the grinding was back.
Im thinking flexplate. The TC bolts where ok but I think ill drop the inspection plate pull the TC bolts out and pry the Flexplate to see if the bolts at the crank are loose, missing, or anything..
Anybody have some info for me?
thanksHasta

I took the inspection plate off. Removed the tc bolts, pryed on the flexplate. I didn't see anything really out of the ordinary. Reinstalled bolts with Loctite. Ran the jeep with the plate off, it looks to me like there is a pretty good wobble in the flexplate. It looks like its about 2mm runout, also the tone ring has a good wobble to it too.

If you put it in drive, stand on the brake and give it gas (i.e. not moving) does the noise still happen?

No, it's all quiet power braking it

I shimmed the rear axle so now the angles are identical. Again, no vibration but still have grinding noise from the tcase. I can get up to speed and shift in to neutral on the trans and get the noise regardless of where the throttle is at. I'm back to thinking it's the tcase. It does it in 2hi and4hi. I don't think its the chain. Possibly input gear or mode hub? The clack noise is also coming from the tcase. If feels like there is too much free rotational play

put it up on jack stands and put it in gear. You might hear it then. If it does have a look. Watch for spinning parts.

I have done that a few times on a rack, Its nothing external. It doesn't sound like transmission. Definitely coming from tcase.

Exhaust hitting cross member?

No exhaust clears everywhere, all new mounts too. The exhaust is new with cat delete