After a run at the track or just testing on the street. upon firm braking as the truck is slowing I get noise in the front diff.

It seems to be more prevalent the lower the speed and the harder I brake.

No noise under acceleration or cruising speed.

Is this normal or should I be on the look out for something?

Thanks

-brad

 

Shift to 2 wheel once you are coasting.

I'd start by measuring the circumference of all 4 tires. Anything over 1/4" difference is putting your 4x4 in a bind. That by itself will create some noise, and accelerated wear.