Strongly agree, I think any symptom could possibly be related to many issues when the car gets to this age and particularly for the people who buy used one and don't know the history of the maintenance clearly like me. Before that, I always try to find a solution for truth when I facing an issue with my LC, but after many DIY repairs I start to understand the only thing true is "the car is an old car and when you got it, it already that old", then there is no idea that doing a single thing can entirely cure the issue...So I just try to start somewhere when I found an issue now, and maybe fix some other issue accidentally...For example, I got the “shaking when red light" issue a couple of months ago, I have no idea what to do. then I start to replace my brake pads because the pads are worn, then the caliper because the caliper freeze, then the brake booster assembly because it can not pass the pump timing test, I never expect it will resolve the shaking issue, but the issue is finally gone after all of these repairs...Maybe not relevant to the vibration but I can see your point if it was shudder that you pointed to.
How many miles (over 200k?) Could be ujoints, but that vibe will present more pronounced as speed increases- less noticeable under 45 mph
could be drive shaft balance, worn CV axles, etc
read up on diagnosis here:
Pulsing/droning vibration at highway speeds
This diff bushing won't cure driveline vibes. Even brand new the bushing flex's quite a bit. Replacing that may help cure a portion of the D-N-R clunk but thats about it. Driveline vibes are hard to isolate with out removing prop shafts one at a time and test driving with CDL locked. Once you...forum.ih8mud.com