You are right, it shouldnt be a problem. That was last year. Granted, I had 15w40, one failing battery and old glow plugs when that happened. I haven't experienced those temps so far, but here is my prep : This year I have brand new glow plugs, 2 brand new oversized batteries from Costco(795ccax2 for a total of 1590cca) I'll be putting Rotella T6 0W40 diesel specific oil and Hot Shot Anti-gel on every gas tank, also new fuel filter. I'll give that a try and report back once the temps get down. Its a bit extreme but I cannot afford to not go out regardless of weatther ( last year there was a full week of -35C and under)The truck shouldn't struggle to start in those temps at all. My experience is more with the KZ engine that I have, but that fires up no problem in -10c weather. Maybe one crank longer at most. Are your glow plugs in good condition?
Also, does your center diff light on the dash flash or go solid? Flash means trying to lock, solid means it's locked. Do you have a rear diff lock as well? Normally that can only be locked after your CD is locked.
No center diff light at all when switching from 4H to 4H locked. Im gonna go thru the wiring
Rear diff is LSD