I just took my truck to a shop to clean up a major rear brake problem (frozen wheel cylinder, soaked shoes, rusty parking brake parts). The guy calls me a few hours later and says "You're not going to believe this but BOTH of your rear sping shackels are rusted completely off the truck!" I don't know how I drove this without losing the drive train. NOW the problem - when I hit 68 mph the truck starts to shake like a massage chair! They balanced the 4 tires ( I trust the guy on balancing) but it still vibrates at speed. What next? I think the problem was there before but because the springs were not in contact at the rear mounting point, I couldn't feel it. Any ideas?
How hard are the u-joints on Rangers? Any tricks I have to know about?
Thanks for reading this long post.
Kimmer

 

is your truck lifted or lowered my buddys s10 is lowered and his truck would shake we shaved 2 inches off his drive shaft and it solved the problem..

 

Take a tape measure and starting from the drivers side front wheel , hook the tape to the forward part of the hub (you may need an extra pair of hands).
Measure back to the center of the rear hub .Note the measurement .
Do the same on the passenger side.
Do they match ?
Oops make sure the front wheels are straight first.

 

I'll try that measurement tomorrow. I was just thinking...the truck is stock height but I'm sure it was riding lower for a long time with the rusted out shackles and brackets. Now that the brackets have been replaced it looks a few inches higher than before it was fixed. Maybe I'm closer to the angle limit and it puts more stress on the u-joints? They look original at 150k miles.

 

BTW Thanks for your responses - sometimes I don't know where to turn when I have a prob with the truck and then i remember all the great posts on this site and always get good feedback.

 

check your tie rod ends. i got mine balanced and right when i hit 65ish it was still shaking. got it on a lift again and my inner tie rod was going. replaced it and it no more shaking and i didnt even think the tie rod would make it do that

Also got it aligned after i changed the tie rod.

 

I had this problem with my 98 and it ended up being the front drive shaft yoke was bad.

 

That's kinda where I'm leaning...the universals look rusty and have no grease fittings so they probably need replacement after 10 years in new england road salt.

 

your tires may have developed flat spots because the tires were bouncing.this happend to me when shocks went bad.only thing that fixed it was new shocks tires and alignment.

 

I don't know...I watched the balancing and the outside seemed pretty stable as they rotated. Oh - I switched the fronts/rears to check for a bad tire and it still shakes in the rear at speed. It's so hard to know what the problem is, no?

 

had this problem my self for me it was my rear u-joint it was toast.

 

jack the front end out and check the tie rods, and while your at it you might as well check the ball joints, then check the u joints.

 

Usually shaking at high speeds like that is indeed wheel balance and even a separating tire, but as you said the balance should have caught that. I'd swap the fronts to the back just to make sure, as it takes it being seriously out of balance on the back to cause the truck to shake. Do you feel it in the steering wheel?

So I'm with you its probably driveline related. Its easy to check all the joints and yokes, just put it in neutral, grab on each side and see if there's play.

Interesting on the toe rod ends causing a high speed shake. Not common but worth checking. And a good to check all the front end parts while you're at it. Are your shocks old? If the re and re on shackles caused one to leak then the shake could be a rear tire drumming at high speeds which can cause a heck of a shake. A buddy's Mustang came out of the shop once with a shake and it turned out to be loose lug nuts... After being a front end mechanic for many years and fixing a lot of bad work I tend to check everything for tight after getting anything done at a shop.

Sorry for the long post. Good luck!

 

Thanks for your ideas, Martin. I swapped front/back with no change. I don't feel much in the steering - pretty sure problem is behind tranny and not in front end. Have new Ball joints and steering parts. There's no 'play' in the u-joints but everything looks kinda rusty and I'm thinking they are dried up. Maybe I should change them just to be sure. 150,000 miles is a lot for original u-joints, no?

 

So it shakes ONLY around the 70mph speed? If so then Im thinking tires

 

It's more like anything over 65...usually with tire balance problems, it goes away when you go even faster - this just gets worse at higher speeds. Since I've had the back tires on the front and felt no shake in the steering, I'm kinda ruling out tires.

 

is it a fast shake like as fast as the driveshaft would spin? "BRRRRRR"
or is it a slower shake like a tire? "wop wop wop"

sorry for the sound discriptions but itll help narrow it down

 

Interesting question....now that I think of it, the sound is at somewhat of a high frequency level. More like the driveshaft and not a wop-wop-wop like tires. Good call.
I noticed something else today: They bolted the shackles on with the bolts coming through the wrong way and they bottom out against the frame. This might be hard to picture but what it does is bind up the shackles against the frame which might keep the rear from floating free and also transfers ALL of the wheel movement and vibration RIGHT into the frame. What do you think of that?

 

if it is the stud of the bolt that sticks through too far just cut it off at the nut

 

I guess I could do that but I'm kinda ticked off that those guys put it together like that in the first place, ya know?

 

take it to them. they must have been blind

 

Just stopped by the Ford dealer - he says that his guys occasionally get the bolts in backwards and hack off the extra to keep them from binding up. Then I stopped by the shop and they appologized for the problem and said they would switch them around.
More later after my test drive........

 

Could a shake be from low tire pressure? I hit the highway and as soon as i went over 60mph it started vibrating a lot. My tires had dropped from 35psi to 30 (all 4) and I filled them back up afterwards. Haven't gone back on the highway yet, so i dont know if its any different. Is that a possibility?

 

Tire pressures are okay - @32lbs. I had the shackle bolts trimmed to keep them from hitting the frame and that seems to help at lower speeds - nice smooth ride. BUT over 60it starts to get a high frequency vibration that I'm starting to think is the drive train, as toreador4x4 suggests. That's the next thing I'm going to attack.

 

I found these video segments helpful....

http://www.expertvillage.com/video-s...le-u-joint.htm

Make sure you don't break the bearings like I did in 1 of the new u-joints. It resulted in me breaking my phone on concrete versus putting u-joint threw windshield.

I didn't think my u-joints were bad. I didn't feel much of a vibration or hum at high speeds (also running mud terrain tires though). However, I did get a killer hum at low speeds; about 20-35 mph. I replaced the u-joints (3 total: 1 at front differential and superlift drive shaft and 2 on the rear driveshaft) and no more hum or vibration. Truck rides smooth. Regardless if you're 4x2 or 4x4 make sure you replace both ends of your rear drive and at least the u-joint at the front differential.