What other than bad U-Joints and Double Cardon Joints causes this? The other day when I was driving 90 miles home I had no problems. Then when I parked my truck at work and got back in it four hours later and proceded to accelarate to about 65 on interstate I felt a very definded shudder that wasn't there four hours ago. I climbed under my truck and went through the procedure that the Haynes manual explains to check the joints and the only movement I could get was just a hair at the slip yoke, so slight that I could only feel it once out of ten times.

Sorry but I have another question. Is it normal to be able to turn the driveshaft while the truck is in nuetral and not move the truck. I could turn my driveshaft and hear gears engaging in the diff. and up front and the truck would not move until I turned the shaft about 1/16th of a turn(approximate)?

 

maybe?? it's the drive shaft yoke?? just my 2cents i'm not an expert by any means

 

POssible that you threw a weight from one of your tires? Could just need balancing.

If the only slack you are getting is about 1/16th, then you should be fine. There is normally a little slack or "play" in the drive line. The noise you hear is just the gears engaging from one direction to the other as you turn it. One thing to do is move the gear selector from drive to reverse and back a few times. If you hear clunking as it shifts, then it could be U-joints or a sloppy t-case.

 

does the shudder seem to be isolated to one wheel? Is it more pronounced at a certain speed range? If so, BB69 is prolly on the right track with the wheel weights. If not, I'd still check the tires... but also be sure that your hubs are properly disengaged. Then check to make sure there's not too much "back-and-forth" play in your rotors. That could mean a hub going bad. By back-and-forth play, I mean: take your front wheels off (one at a time, of course ) and while looking at the rotor, grasp each side like a steering wheel. if it moves easily in any direction other than as if turning the steering wheel, pull the hub apart and inspect it.

I had a problem like the one you're describing and ignored it until finally one of my brake pads popped off. Bad times... when I checked the play in the rotor it was really loose. So loose that the caliper pushed it in one direction enough to allow the back side pad to come off. I took the hub apart and found it all ground to bits... more bad times. luckily, $100 for a new set of Warn premiums plus $30 for a new set of lock washers and locknuts (what they call the manual hub conversion kit), throw in a little grease and a lot of time and cussing... it was better than new.

I'm not saying this is for sure what you've got, but it's definitely worth a check. If I had let mine go much longer, my front wheel would have popped off (rotor, caliper, and all) and some real damage would have been done.

 

96 351 auto.

I have the same prob. mine starts at 73 mph and gets worse as you go faster. rear view mirrors are blurry from shaking! I pulled rear drive shaft and drove it in 4x4, acted the same, but I changed the u-joints and double cardin bearing anyway. I need to get it to the shop and check tire balance, but since most of the driving it gets is around town and towing a camper, I dont get above 65 too often. Hope it's your tires out of balance, if not, let me know. . .

Rich

 

What kind of tire do you have? Mudders or street radials? Could be possible you threw a belt in one of your tires or if they are mudders you may have lost a chunck of your tire on the inside wall where you can't see it. Might be something worth lookin at.

 

Did replacing the u-joints help any? My bronco shudders at that speed and pops suggested that. Would cracked rubber body mounts have anything todo with such a shudder? I also add that I still have the crappy cheap shocks the previous owner had on her. -Bill

 

No change. I am hoping it is just the tires.

I watched the guy rebuild this driveline, he used a modified air hammer, for impacting rivets. He would vibrate the yolk and the u-joint would work its way out--no 20lb hammer blows. Then he spot welded a bolt to the old cardin joint bearing and 'vibrated' it out. He also pulled the slip shaft apart and lubed that. Then to top it off, he painted it! All for $40.00 labor on a Saturday.

 

Well i have a similar story. '82 4 speed I6...
I had my front wheel bearings replaced (both sides-inner and outer) had the driver side blow out on me. My mechanic said the axle spline was OK but had water in the seal and then bam!

Before that the alignment was getting off after a summer of logging roads. But there was no shudder just a slight pull to the right.

After the bearings were done now i have a shudder and what sounds like brakes grinding at low speed.

So now i am getting an alignment and balancing-the Uni joint is getting old but not too bad at the moment. I will reply once done...maybe it will shed some light on this problem.

G

 

96greenbronco and buckeyebronco, did you guys figure out your vibration problems????

I have the same problem and already replaced my tires and wheels and it did nothing to get rid of the vibration.

 

I didnt read back up through all of the posts, but another item to look at is the u-joints. Check those to make sure there is no play in them. Also drive shaft balance can cause high speed shuddering.

What about your shocks? If they are bad then slight bumps can cause rapid bumping of the tires that feel like a shudder.

Just a couple of items to look at.