Re: 4x4 problems- 99 Ranger
Do you switch the transfer case mode before or after the truck is up to operating temp when you park it outside in the cold? If the truck is warm when you switch to 4HI there shouldn't be a problem.
I can see the cold affecting the switch if the switch is vacuum controlled. Any condensation in the line will freeze overnight and cause pressure problems. If you haven't had the transfer case fluid changed in the last two years, it'd be worthwhile maintenance item to perform.
If the switch is electronically controlled I would lean toward replacing the TCCM (transfer case control module). I'm not sure of prices for the Ranger models but would guess around $300.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!