After an exhaustive search through as many vibration threads as I could stomach, I think my situation is a little different, but please point me in the right direction if I'm wrong.
So the situation: My 80 is a mostly stock example, factory wheel size, OME stock ride height replacement suspension (which advertises a 0.25-0.75 inch lift), rebuilt the knuckles last spring, new wheel bearings, and mostly new bushings with the exception of the radius arms.
Before the holiday, I started to get a nasty vibration from 25-40 mph. Had the tires rotated and balanced as a sanity check, but it made no difference. Got it in the shop to replace the u-joints on the front driveshaft. Initially it felt great, but after about 25 miles, it started to feel rough at 70 mph, then maybe a mile or two later the brand new u-joint at the front differential broke (at 70 mph, in traffic, at 6:00am). One of the bearing caps was missing, but the driveshaft was connected. I limped it off the highway at 10 mph; any faster was quite shaky. Had it towed back to the shop.
The shop claimed the yokes were out of alignment which is what caused the second failure. They realigned it, balanced it, and installed new u-joints again. Then after a 20 mile test drive, they sent me on my way.
Again, it felt good initially. I decided to take it on a highway drive over the weekend to regain my confidence which ended up having the opposite effect. I did an 80 mile round trip drive on a 65 mph highway that has sections with a 4-6% grade. On the downhill bits, I was getting a rumbling at around 70 mph. Now, it's pretty much always had a slight rumble at highway speeds, but this was noticeably worse than before all this happened, although not quite as bad as before the u-joint failed a few days before. At this point, it's still smooth at all other speeds and it's smooth at 70 on flat ground, but I decide I'll keep it off the highway until I can do some troubleshooting. I'll note that I inspected the driveline multiple times and nothing looks out of the ordinary.
Fast forward to yesterday, on the way home from the grocery store I start to notice that low speed vibration coming back.
So to recap, replaced u-joints, one came apart 25 miles later, balanced driveshaft and replaced again, noticed off throttle vibration at 70 mph, and now feeling a 35 mph vibration coming back after about 130 miles since the second set of u-joints. All vibrations are very noticeably coming from the front of the car.
I have every reason to believe the shop doing the work knows what they're doing. They specialize in old Land Cruisers, but I'm not ruling out workmanship issues. That said, I'm starting to think they're mistaking the u-joint problems as a cause, when they're really a symptom of some other problem, or that the u-joint failure caused some collateral damage
So finally! My questions! Is it possible for u-joint problems to be caused by something else in the driveline? I.E. T-case, pinion bearing, etc? Can worn radius arm bushings be worn enough to cause pinion angle issues? Could the u-joint failure at 70 mph have damaged something in the driveline that's causing the increased vibration? If so, what parts should I be looking for damage to? I'm planning to pull the front shaft tomorrow just to really make sure the problem is coming from the front; is there anything I should be looking for while I'm in there?
Thanks in advance.
So the situation: My 80 is a mostly stock example, factory wheel size, OME stock ride height replacement suspension (which advertises a 0.25-0.75 inch lift), rebuilt the knuckles last spring, new wheel bearings, and mostly new bushings with the exception of the radius arms.
Before the holiday, I started to get a nasty vibration from 25-40 mph. Had the tires rotated and balanced as a sanity check, but it made no difference. Got it in the shop to replace the u-joints on the front driveshaft. Initially it felt great, but after about 25 miles, it started to feel rough at 70 mph, then maybe a mile or two later the brand new u-joint at the front differential broke (at 70 mph, in traffic, at 6:00am). One of the bearing caps was missing, but the driveshaft was connected. I limped it off the highway at 10 mph; any faster was quite shaky. Had it towed back to the shop.
The shop claimed the yokes were out of alignment which is what caused the second failure. They realigned it, balanced it, and installed new u-joints again. Then after a 20 mile test drive, they sent me on my way.
Again, it felt good initially. I decided to take it on a highway drive over the weekend to regain my confidence which ended up having the opposite effect. I did an 80 mile round trip drive on a 65 mph highway that has sections with a 4-6% grade. On the downhill bits, I was getting a rumbling at around 70 mph. Now, it's pretty much always had a slight rumble at highway speeds, but this was noticeably worse than before all this happened, although not quite as bad as before the u-joint failed a few days before. At this point, it's still smooth at all other speeds and it's smooth at 70 on flat ground, but I decide I'll keep it off the highway until I can do some troubleshooting. I'll note that I inspected the driveline multiple times and nothing looks out of the ordinary.
Fast forward to yesterday, on the way home from the grocery store I start to notice that low speed vibration coming back.
So to recap, replaced u-joints, one came apart 25 miles later, balanced driveshaft and replaced again, noticed off throttle vibration at 70 mph, and now feeling a 35 mph vibration coming back after about 130 miles since the second set of u-joints. All vibrations are very noticeably coming from the front of the car.
I have every reason to believe the shop doing the work knows what they're doing. They specialize in old Land Cruisers, but I'm not ruling out workmanship issues. That said, I'm starting to think they're mistaking the u-joint problems as a cause, when they're really a symptom of some other problem, or that the u-joint failure caused some collateral damage
So finally! My questions! Is it possible for u-joint problems to be caused by something else in the driveline? I.E. T-case, pinion bearing, etc? Can worn radius arm bushings be worn enough to cause pinion angle issues? Could the u-joint failure at 70 mph have damaged something in the driveline that's causing the increased vibration? If so, what parts should I be looking for damage to? I'm planning to pull the front shaft tomorrow just to really make sure the problem is coming from the front; is there anything I should be looking for while I'm in there?
Thanks in advance.