Driving along a quiet street or alley with a wall on one side allows one to hear many noises. Some noise with a higher frequency than driveshaft could be countershaft. Pinion bearings usually will whine upon accel. coast. Throw out bearing could have noise changed by clutch application. Trans. bearings, driveshaft, pinion bearings would have higher frequency than rear axle bearings.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.