I"ve noticed a steady vibration that starts at 30-32mph building to a cresendo around 35-38mph then smoothing out. It seems to come from the rear-end area, no accompanying noises...seems to independant of whatever gear I'm in and does not do it when slowing down and passing through the speed ranges.....I'm in a 92xj 2wd with about 173000 on the clock anyone got any ideas?

 

What are your u-joints like? Sounds like plain old driveline vibes. Are you lifted?

 

U-joints are a good idea, I'll check them out this evening...what do I need to look for?? no, it's all original!