I have a vibration and a droning noise between 70-80mph. Based on the rather high frequency, I'm assuming it is the rear driveshaft. It's an OEM setup with about 94K miles on it ('96 5.8, E4OD, 3.55's, 265/70 R15's). Can't feel any play in the U-joints or CV joint. Doesn't look like it has lost any of the balance weights.

Thought about having it rebuilt and rebalanced but its about $200 and I'm not sure the driveshaft is the problem. Ford wants about $400 for a new one.

Any thoughts on other high frequency vibration sources? Anybody replaced or rebuilt the OEM driveshaft without the CV joint? Any good aftermarket driveshafts available at a reasonable price?

thanks

 

I have over the years (187,000 miles) replaced both the double cardigan joint and the rear u-joint (2x). Everytime they looked fine till they were pulled out of the truck and really looked at.

Does the vibration go away when you let off of the gas? If not I doubt it's the joints, and unless you banged up the driveshaft or lost a weight (look to see if you notice any missing) you might be looking at something else. I've had a front wheel bearing go loose on me and cause similar symptoms to a bad u-joint (though I was suspecting the front driveshaft at the time since it only happened in 4wd).

 

Who drives a Bronco at 80 mph anyways.
You must have too much money to spend on gas.

 

You may have a bad brearing in the u-joint, it will not feel loose, but will vibrate. Changing the u-jouints is cheaper than the drive line. My .02 worth.

 

On my 86 Bronco, I am running 35's with 4'11 gears. I was getting a squeak while I was on the gas. The squeak developed into a bad vibration. Dans Driveline in Las Vegas had to cut the yoke on my rear shaft and reweld with a greaseable needle bearing and new u-joints for $285.00. Solved the problem.

 

I paid $350 for a new rebuilt and balanced shaft, installed. I know that the price was a little high, but the improvement in the ride was worth every penny. The truck was already in the shop because I thought that the t-case was bad; when they told me that it was the driveshaft and not the t-case I didn't mind spending the extra $50 to have them install it and just pick the truck up and drive away, rather than have to push it out of their shop and put the shaft in on the side of the road, in winter... Come to think of it, that was $50 very well spent!

Generally, the joints will bind; and you cannot feel this while the shaft is still on the truck. Rather than get loose, they actually get tighter in part of their range of motion. You have to take the shaft off and rotate the joints through their range of motion, and then you can feel the bound up areas.

 

Is it you wife trying to get you to slow down ?
I think sfitzgerald351 is right about the double cardigan joint,100,000 miles is about the right time to replace it.

 

HMA, make sure the driveshaft has been installed "in phase", with the U-joint end caps aligned with each other. If the driveshaft has been separated at the slip-yoke, it may have been re-installed one spline off......

 

Thanks for all the replies. I have had the driveshaft off a couple of times and never felt anything being loose or binding, but I agree you can't always feel these things especially without the load applied. The vibration occurs even with the tranny in neutral coasting down a hill at 70-80 mph. I think I will go ahead with the driveshaft rebuild. Thanks again for all the good comments.

As for driving too fast, I guess I'm too use to my '93 stang (runs a 12.3 quarter @ 109mph). Giddyupp.

 

Don't forget to check / lube your slipjoint. It can cause a few problems but maybe not necessarily vibration. Anyway, while the shaft is off, only takes a few more minutes to disassemble and reassemble it.

Good luck,

 

I would check this first. JB is right on. Very common problem. The bearings get dry and the joint gets stiff. I have found this the most common problem of u-joint vibrations. If there is a vibration and the joints aren't loose, I always pull the shaft and rotate the joints to see they move freely and smoothly.

 

Did you get this fixed?

 

Took the driveshaft to the shop yesterday. They said it felt ok but also mentioned it could be "out of phase" from the original balance. Couldn't check balance because they balancer was not working. Took the driveshaft home and indexed it 90 degrees (bearing caps aligned) and put it back on. Drove it this morning to work and vibration seems to be at a different speed. Plan on indexing it another 90 degrees and repeat the process until it solves the problem or determine its not an "out of phase" problem.

Doesn't make sense to me. I would think each half of the driveshaft was balanced independently. If it was balanced as an assembly, why wouldn't it have been keyed or marked so it could only be assembled one way. Go figure.

 

I have read a million threads in here regarding road vibration. What I have is an 86 5.0 EFI with a 4 speed manual. My truck has a vibration that is really bad around 65-75 and pretty much goes away after 80. I still can kind of tell it's there, but it settles down big time after 80. Anyway, I have removed my rear drive shaft and just drove with the front differential so that ruled out the rear u-joints and the rear pinion. Then I put in the rear drive shaft and took out the front shaft to rule that out. I checked the front steering and it is a bit worn, but not loose enough to cause such a vibration. The radius arm bushings are fine. The wheels and tires I have replaced (talk about wasting money trying to chase a problem down). The wheel bearings are fine. The engine mounts and trans mounts are new. I checked fluid levels in the front and rear diff, the transfer case and the trans. The trans is old and there was some metal debris in the bottom of the case when I changed the fluid, but it still functions perfectly.

So here is my point. I have searched and read through TONS of vibration threads on this site. I have done my homework. One thing I have noticed is that on all these vibration threads, a bunch of people give great advice and suggestions, but I have not read one single thread where they actually post what solved the problem. Please post when you solve the problem, and I promise to do the same!

 

I did the same thing you did - removed the rear DS and drove it with just the front. Did not notice any vibration, but didn't drive it very far either.

My problem started after I took my rear DS apart to grease it (in an effort to solve a clunking noise which actually turned out to be a problem with auto locking hubs). I may not have put it back together exactly how it came apart although I thought I did. About the same time I put new, smaller tires (265/70R15's) on it replacing the 32" BFG's that came on the truck when I bought it. This in effect made my DS turn faster than it had before.

Had this same problem on my Mustang. All was well and then did a gear change from 3.08's to 3.55's. Higher DS rpm's made it vibrate. Bought a new Ford Racing aluminum DS and problem solved (turns 5000 rpm through the quarter mile with no vibration).

Will keep you posted.