Toyota Repair: 98 tacoma 4X4, 2.7, 5-speed, manual hubs, manual hubs, clutch release

Question
I have a problem with the truck hesitating and shaking. It started intermittently when I up-shift. I have felt it occasionally on downshifts and under hard acceleration. It only lasts for a few seconds. The engine seems to be running fine, idles good etc. I think the problem is in the drive train, but it happens so quicky I can't be sure. The truck has 205K miles and the clutch has never been replaced. Other than the famous Toyota squeak ( that no one has been able to fix) when depressing the clutch peddle, I have had no drive train problems. The problem is occuring with increasing frequency, so I would appreciate any suggestions. Thanks!

Answer
It may be that the driveshaft is out of balance but a more likely problem is a worn U-joint, what I suggest is remove the driveshaft and have the U-joints replaced, the one in the rear is probably the problem, check it for any looseness, at this mileage it may be a good idea to replace all of them.
There is a fix for the squeek and toyota has issued some service bulletins, the squeek is either coming from the pivot point of the clutch release arm in the bellhousing which can be lubricated by removing the rubber boot and spraying grease into it, or the pedal is squeeking, in that case the pedal bushings can be replaced.