86 B2000 motor has a "whir" when accelerating

I'm in the process of moving and have to be out by the end of the month so my diagnostic time is minimal right now. Hoping someone else has experienced similar before. When accelerating a whir is produced at approximately 2500Roma and up in each gear. The truck has 165k on it. It does have AC though the controls are not hooked up, the belt is hooked up to the compressor. Any ideas?

I had that once. Not sure if yours is the same, but mine turned out to be the outer race for the transmission input shaft bearing had a crack in it.

Last fall I removed the three belts on my '88 B2200 to try to track down a small noise/vibration while accelerating or decelerating. I did find that the AC clutch bearing was somewhat bad, so I replaced that, but even with that belt disconnected, noise remained. The PS idler, the alternator felt OK.

On mine, turned out to be the two motor mounts, both were broken. The new mounts were $13 each through O'Reillys.

So easy to check: remove the bottom nut on each of the two motor mounts. Use a block of wood and a jack and jack up the engine about 1 inch. It should be pretty straightforward to tell if your mounts are then broken, like the bottom motor mount stud should be loose/wiggly.