4405 potential problem after install

[97sprt4x4]

Yesterday i installed a JY BW4405. i tested it out today to see if it would solve my 4wd problem. to do this i hooked myself up to a tree and slowly eased onto the gas to see if i could get the wheels to slip and engage the fronts in the dirt. it worked in A4wd, it worked in 4wd and in 4low. This is all good i have 4wd again. something that's a little concerning is in 4wd there was a slight grinding noise when the tires started to spin. however the noise was not present in 4low. or A4wd did i install the case wrong??

Thanks in advance,
Justin