Click Clank noise when backing up ??

I'm new to tractors as well as a new member of Orange Tractor Talks.
I have a two month old L3301HST, I was backing up yesterday after an oil change, no implements attached, I could hear a low level noise while backing up. Sounds like a click clank click.

I also made a brake adjustment as the pedal seemed to have a little too much free travel. I backed off on my adjustment to as it was, but noise was still there. The sound is similar to what I have heard on trailer brakes that have a broken brake spring. Thats why I mention the attempted brake adjustment. I have on two occasions, started movement of the tractor with parking brake on but realized by the sound of the HST whine I forgot to release the P brake.

Can anyone say if this noise is normal while backing or could I have brake or other problems?

I may have solved my on mystery on the noise I hear while backing up.
After doing some research on wet brakes, the disk in wet brakes are known to bump together causing a click or clank noise when the wheel is in motion.
When looking at a cutaway view of how wet brakes work it is understandable.
With any luck, this is what I hear and there is nothing wrong.
FYI, the noise was very slight clatter at idle in midrange slowly backing up, could not detect at higher ground speeds.
trying to be optimistic but wisely alert at the same time. If I'm correct, perhaps this may be of some value to someone else.

KENB2920,
I have been guilty of not being fully disengaged with 4WD. I believe I was fully disengaged when I heard the noise, however, I'll keep that in mind and check that next time on the tractor.
Thanks, for your thoughts
TN Road Dog