Transmission issue in cold weather

[Sand]

I had an issue this morning where I put my HMMWV in drive and it wouldn’t engage. Same with reverse. It finally did after a little back and forth. It was unusually cold today and I was wondering if I just need to let it warm up longer to not have this issue.

 

[Jinx]

I'm by no means a transmission expert, but this sounds like a classic case of the tranny fluid being too low.

 

[Thunderbirds]

Temperature wouldn't affect it like that by itself. Sounds like a mechanical issue of sorts...

 

[Mogman]

I had an issue this morning where I put my HMMWV in drive and it wouldn’t engage. Same with reverse. It finally did after a little back and forth. It was unusually cold today and I was wondering if I just need to let it warm up longer to not have this issue.

Have you changed the fluid and filter? a partially clogged filter can cause this when the fluid is thicker.