Vibration while accelerating in first gear

2001 XJ 4.0L AW4 2" lift 31" tires...

Had her out in the desert last week and when i got back on pavement I started noticing a grinding sound and vibration under harder acceleration in first gear.

Now, when I had it off road I didn't do anything overly abusive except once when it was in 4lo and I gassed it pretty hard, lighting up all 4 tires.

I have searched for anyone having a similar issue, and I found a couple of instances where this grinding was due to a stretched transfer case chain. But, others suggested that you shouldn't feel this vibe when in 2WD. Stretching the t-case chain seems plausible since i did gun it pretty hard in 4lo, but if I shouldnt be feeling that in 2WD, what could it be?

Thanks for your help

drain a little fluid and see if chunks come out?
Sorry not much help with the AW4
Also which T case you have my help

Sorry, the T-Case is the NP231

I am going to drain the fluids tonight, some said you can simply put your finger in there and check the chain tension?

it may be possible to check chain tension through the fill hole, never tried that

The with a 231 I would think the chain would still spin, as it is connected to the front axle. As there is nothing disconnecting the chain from the front output, only from the t-case main shaft to the chin itself.

If you are without an answer after draining the fluids, I would say pull the front shaft and see if there is any difference.