4wd Steering Pulls to the Left

Well, its definitely winter in the Great White North (Minnesota) so have been using 4x4 wheel drive quite a bit. When at higher speeds (40-50Mph) the steering is pulling to the left. This seems to be only happening when in 4x4 - I can drive down the same road, same speed, 2x4wheel drive and it does not pull at all. Is there any reason for concern? Is this an indication of a future failure in some part of the 4x4 drive? Any ideas are appreciated!

 

I would have the alignment checked first. Tundras can be sensitive to alignment, wheel balance, etc. What kind of tires you run? Some tires can have a radial pull, which could be more noticeable in 4wd. Or there could be some 4wd problem, one side not engaging properly.

But I would start with the easy, most common thing first, confirm good alignment. If that checks out, an issue with that side cv, hub, tie rod would be next to check I think.