Drive train vibration first few miles then OK. 2002 Isuzu Trooper.
2002 Trooper 2WD, 80K. First mile smooth, 2nd and 3rd mile I get a mild to rough drive train vibration when trying to hold a steady speed (i.e. 40MPH). I ease off gas, it goes away, I speed up moderately, it's not there. Only under steady speed and mild acceleration does it show up, and only in the 2nd and 3rd (or so) miles. Then it pretty much goes away. Any ideas? My trusted shop says new motor and tranny mounts and replace U-joints. Not so sure, especially for $1200. Rear differential fluid issue?