Bad driveline vibration...Please advise...

[KSDMED]

I have a stock driveshaft and I am not too far from you.

[pstocker]

Got under my SVO tonight...

to rotate my tires to see if that would help my vibration issue. While under the car, I checked out the rear flange to differential bolts and they were all tight. Someone has replaced the u-joints (I am guessing the previous owner), and they used the ones without grease fittings. I reached up and grabbed the DS behind the yoke and checked for play and I did feel a little bit, I can't really say how much, but it felt like it was in the tail shaft, possibly the bushing. There was no fluid leaking from the tailshaft though.

After I got the wheels off, which felt like maybe they were installed with a torque wrench used to torque wheel onto a semi (yep, I had to stand my 310 pounds and bounce on the breaker bar to break the f'ers loose, stupid....), I rotated them front to back, put the wheels back on (with the proper freakin torque I might add!!! Geesh!!), and took her out for a spin. The vibration was noticeably less, not gone, but less, and I am pretty sure it was not a placebo effect.

A couple of questions, should there be any play in the tailshaft? I was told by the previous owner that the car did sit for a very long period of time and not move (belonged to a friend of his who parked it). He told me he thought the tires had gone a little square. I will say that the steering wheel did vibrate after rotation where it did not at all before. What is next, should I install a new tailshaft bushing, or just get some tires and see what happens?

[pstocker]

Ok, so it was wishful thinking....

I get on the highway this morning and the vibration is still there, just as bad, I hate the placebo effect! My hopes were flushed down the toilet for an easy solution yet again!

If I replace the DS and the tailshaft bushing and this vibration persists, could it possibly be clutch related? I do have a ver strange noise coming from right in front of the firewall sometimes when I first take off. I can really describe it to well other than to say that is sound like the clutch hub is slipping or something crazy! It is a very loud noise that only lasts for maybe a second or two and is very inconsistent. It does seem to happen more when it is raining out. My clutch is getting kind of bad as it does not engage until almost at the top of its travel.

So much stuff!!

[jkboyd]

Did you check to see if the damper on the front yoke is lose? The rubber deteriorates and they can cause problems. Are there any dents or dings in the driveshaft? I took mine to a driveshaft shop and they inspected and balance it for $60.

[pstocker]

Did you check to see if the damper on the front yoke is lose? The rubber deteriorates and they can cause problems. Are there any dents or dings in the driveshaft? I took mine to a driveshaft shop and they inspected and balance it for $60.

It didn't feel loose. The play I was feeling was the yoke in the tail shaft of the trans.

[THESVOTRUST]

Why don't you adjust your clutch quadrant now (to see if it is just out) ?

Grab the pedal and lift up (toward the steering column) should hear it ratchet -might have to do it twice. The pedal should now be closer to the floor.

Once done you can see if the pressure plate, disc and TO need to be replaced. Does it "slip" under boost in 5th? 4th ? THIRD !!!!???

Really REALLY need to provide more info than what you have!
How many miles?
IS THIS A car with a low oil sender or leaking rear main seal?
Is that sound a "throwout bearing" on it's last leg?

Mark

[Erics SVO]

Define how long it sat. I got my car with practically new tires, but it sat for at least 2 years. Tires were flatspotted to hell....

[pstocker]

Define how long it sat. I got my car with practically new tires, but it sat for at least 2 years. Tires were flatspotted to hell....

I am not exactly, but I would say about a year or more on like new tires. When I spun them on the front, you could a slight rise and fall when you looked at a fixed point behind the tire on the car.

[jkboyd]

Flat spots on the tires will cause a lot of vibration. My car sits almost all winter and come spring I have to drive it around some before it starts to smooth out. I would imagine if it sat long enough they may never get round again. Maybe take the tires to get balanced and see if they can tell if the tires are out of round on a spin balancer.

[Otto Man]

Try and see if the wheels are out of round (up and down, side to side), not just the tires.

[Erics SVO]

If they're not going away after driving a bit with them being properly inflated, I'd say they are done.. I felt like I was riding on wooden wagon wheels.

[pstocker]

The thing is that I get no I'll effects when driving very slowly. Usually, when you go slow enough on out of round tires, you can feel the car go up
And down slightly

[gbeaird]

<SNIP>

You don't have to shell out big bucks for an aluminum driveshaft nor do you need to have one made. Just find an AWD Ford Aerostar minivan in the junkyard...they already have the correct length driveshaft if it's the aluminum version and it will bolt in, but I prefer to install new U-joints & a 1310 series T5 style yoke/flange whenever I use one of those.

Double-check that driveshaft before leaving they JY, though. It seems all the JYs around here like to use fork lifts to move their cars into and out of the junk yard area. Most of the really cool aluminum Aerostar driveshafts I've see had a big divot across the back end from the Aerostar being lifted by the fork lift and set down on the stands.

[gbeaird]

I'd take the car to a tire shop and have them re-balance the tires. That may fix your issue, or they may discover an out-of-round tire. Additionally, since you say someone replaced the u-joints, they may not have bolted the driveshaft back on the differential in the same location it came off. If the tire re-balance doesn't fix the issue, try unbolting the driveshaft from the pinion flange, rotate it 180-degrees and bolt it back together to see if that doesn't help. If so, and it's all good, you may want to mark the flanges on both the driveshaft and pinion flange so this won't happen again.

That all said, my first SVO, a rough 84, had suffered a u-joint failure at one time in it's life (side-stepping the clutch at 5000 RPM). The PO mentioned it. The car had a bad vibration like you describe. After chasing a bunch of bad leads, I discovered that it appears the driveshaft had come out from under the car (front u-joint broke) and bent the pinion flange. I sold the car before fixing this.