transfer case oil

just finished changing my LSD, transfer case, and front diff. used mobil 1 75/90 ls in the diff, the old mobil 1 came out looking as new as it did 40k miles ago, same in the transfer case (mobil 1) and front diff. I went with redline 75/90 in the transfer case and front diff this time and noticed it takes alot longer for mytransfer case to engage and gives quite a loud bang when disengaging while driving. I think I'm gonna go back to mobil 1