I have noticed that when it is colder outside (30's) my truck seems to whine like the same noise a power steering pump will make when it is low. As soon as it heats up though the sound goes away. I have not noticed any difference in performance. Just wondering, maybe the tranny?

2002 LB7
73,000

yes, if you're the original owner you should've received a video concerning the Allison trans and the pump noises. To me it sounds like a stuck fan clutch, but living in the midwest it's been like that since I've owned it. Also it doesn't necessarily need to be cold, if it sits for a period of time you can also get the whine in the morning.

yea mine makes that same noise dont know what it is tho no problems

So is it anything to worry about?

without actually hearing it I can't say, but if it sounds similiar to a pump or the fan clutch engaged you're probably ok. Mine normally lasts for 1/2 mile or so at most, even on the coldest days.