Manual transmission 93 rodeo. 169,607 miles. about a month ago i started experiancing a grinding/rumbling sort of feeling while driving in 3rd gear, so bad sometimes the entire dash starts rattling. also when at highway speeds in 4th or 5th gear there is a distinct rumbling coming from the driveshaft or transmission case. any ideas/hints/solutions? (i'm really hoping i don't have to rebuild my transmission)

Manual transmission 93 rodeo. 169,607 miles. about a month ago i started experiancing a grinding/rumbling sort of feeling while driving in 3rd gear, so bad sometimes the entire dash starts rattling. also when at highway speeds in 4th or 5th gear there is a distinct rumbling coming from the driveshaft or transmission case. any ideas/hints/solutions? (i'm really hoping i don't have to rebuild my transmission)

2WD or 4WD? Have you checked the universal joints in the drive shaft. Could be clutch problems.

4wd. where are the universal joints located? also clutch appears to work fine because the grinding/rumbling happens only in the top three gears, but i could be wrong it is difficult to isolate specifically where it comes from and what makes it happen, and it is only the second clutch on the car (over 100K miles).