The car accelerates normally up to about 35 miles per hour. Above that I get a hellacious vibration up till about 50 mph. Let off the gas it goes away. Lightly reapply torque from the engine and the vibration is back. The vibration is the same frequency no matter what gear i am in (3rd 4th or 5th gear with torque).

When I alternate between first and reverse there is a light clunk but nothing monumental. I crawled under there and the u-joints look and feel solid. There is some play in the differential but I can't tell how much

with the back wheels in the air i get the vib but not as bad and I can't isolate it.

My son has had this car for about a year so I can't comment on the onset.

anybody got any ideas? where do I start?

 

check the balance on the tires first.......... then i would check the driveshaft for any dents or missing weights.. then maybe send it off to be balanced.. i would do those first before i ripped anything monumental apart.

 

Just to be clear here, we're talking rattle your teeth vibrations.

 

you need new U-joint in the drive shaft. You will need a new or a custom one.

 

Drive shaft

 

Evil mOtors has the right idea. A driveshaft is expensive (even though that's what is sound like), but start with the cheap stuff.

If the vibration is as bad as you say, try jacking the car up by the frame so the back wheels are off the ground. Get somebody to "drive" the car until it vibrates. You go around the back and look closely at the wheels and make sure you don't have an out of round tire. If it vibrates that bad, the whole axle should jump up and down. If it does, and the tires are not out of round, then it could be tire balance or a bent axle.

The clunk, however, DOES make it sound like u-joints or drive shaft balance, although I too lean towards u-joints.

By the way, make darn sure you put some safetly glasses on in case the tire throws out a rock or something.

 

well if you get one from a junkyard it won't be expensive - it ended up costing me about $35 bucks and low and behold it got rid of a whiny noise the driveshaft was making.

 

Yeah the junkyard is the place to be on this one. Also these driveshafts (ujoints) can be rebuilt, even though everyone says they cant. I got my one of my ujoints totally replaced( hacked off and welded), another ujoint was rebuilt using their press thing or whatever they do . And they balanecd it all for $70.

Before that my ujoints made a terrible scraping noise. But yeah, see if you cabn score one at the yard.

 

I took the driveshaft out and pulled and tugged on the u-joints. They didn't feel loose or have any play at all.

The front one felt a little stiff so I decided to replace both front and rear, $9.97 each at Advance Auto but they won't be here till monday.

When I took the front one apart three of the bearings were fine but the third one the rollers were powdered rust. Think this will solve the radical vibration problem?

 

I've had that happen before with another car. What happens is the drive shaft won't bend through its normal range of movement, and forces the trans to vibrate back and forth on its rubber mount, causing vibration.

That is an excellent price for the joints. The prices I have usually seen quoted are around $45 ea.

By all means once you get them replaced, update the thread or post a new one describing your sucess, and the make and part number of the u-joints. There are a lot of people who will be interested, particularly in Canada where getting the shaft rebuilt by a drive shaft or buying a new shaft costs between $300 and $400. In my area for instance a crooked company has bought up all the RX from the junkyards, and take us to the cleaners.

 

The new u-joint cured it.

This was not as easy as it looked. The rear yoke is angled and I had a time pressing the old ones out. Ended up bending it so I had to take the new ones out to straighten the yoke.

Long story short, I will wait 1000 miles before I declare success or search the junkyards for a new driveshaft.

 

You should search the yards anyway. If the joints were that bad, I wouldn't rely on the shaft to be much better for very long.

 

Part number and make of u-joints you successfully used would be good.

I know of several other peole who have not had success with various u-joint makes, so I would really like to know what DOES work. Thanks.