"Sloshing" transmission noise

[chaseholyoak17]

Hey all, I just got my ranger and I recently have noticed that the transmission makes an odd noise in 1st, 2nd, 4th , and reverse gears. It sounds like fluid sloshing around and is more noticeable in 2nd gear.

-The sound goes away when I come to a stop
-It starts when I move, to the rhythm of the speed of the truck, not the engine speed
-No other noises/odd behaviors of the transmission
-Clutch in, clutch out, it does not change the noise
-No slipping out of gears, or grinding noises
-Freeze plugs in place, no signs of leaks

The truck is a 2.3L with a manual trans (M50D) with 90k miles on it

My last ranger (89 2.9L) had the same problem in all gears and was much more pronounced. I didn't bother looking into it at the time, as it was a salvage title.

Thanks in advance!

camelgrassjuice, I have recently come up with a very similar problem with my '01 Ranger 3.0 5-speed manual. My best guess is that it's the output shaft bearing in the transmission, U-joints or maybe even something in the rear end but I doubt it. Mine makes a high pitched whining noise which is more noticeable at lower speeds in 2nd or 3rd gear. The pitch is proportional to vehicle speed. Lower pitched at lower speeds and higher pitched as I speed up. Usually when I'm going highway speed in 4th gear or overdrive I don't hear the whining sound. Whether I have the clutch in or out or whether the transmission is in gear or neutral it makes the whining sound. Tranny fluid is full and was just replaced a few months ago.
I can tell ya this: it is NOT the throwout bearing, pilot bearing, or input shaft bearing if your symptoms are the same as mine. In my case, it's most likely the rear main shaft bearing or maybe u-joints.