Front end clunk when accelerating uphill in four wheel drive

This sounds like a mechanical clunk due to the lag. So just to clarify, does this do it at all in 2WD?

If not, which system do you have? Looks like there is an electric shift and manual.

Depending on this, it could change the issue but if this only happens in 4WD then we have somewhere in the case and it is most likely not the front axle.

However, when you say there is a lag, does the vehicle lag by not moving or are you saying there is a lag in 4WD engagement?

In other words is this a clutch issue or are you putting the vehicle in 4WD and it is not engaging until you move and then as you are rolling the transfer case clunks and it engages?

If that is the case, that may be normal so can you get a video of this so that we can be on the same page?

One way to try and check that is to lift the 4 wheels off the ground and then engage 4WD. This will have no load on the vehicle and it should just go right in.

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

Lastly, let's just check for codes and make sure nothing is there as I suspect there will not be.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Thanks