Figured it out! For GRUB_DEFAULT, I was using:
Code:
GRUB_DEFAULT="Slackware-14.1 GNU/Linux, with Linux 3.18.18-local"
However, upon running grub-mkconfig -o /boot/grub/grub.cfg, I was instructed to use this instead:
Code:
GRUB_DEFAULT="gnulinux-advanced-e246d5eb-623e-4518-ae21-96df0820c0c3>gnulinux-3.18.18-local-advanced-e246d5eb-623e-4518-ae21-96df0820c0c3"
I'm sure this code will be different depending on the kernel version used and probably other factors. I ran the grub-mkconfig command again, and this time, the correct kernel was loaded. Marking this thread as solved. Hopefully it can be of help to others.